mongos.1

.TH mongos 1
.SH MONGOS
.SH SYNOPSIS
For a \fBsharded cluster\f1, the \fBmongos\f1
instances provide the interface between the client applications and the
sharded cluster. The \fBmongos\f1 instances route queries and
write operations to the shards. From the perspective of the
application, a \fBmongos\f1 instance behaves identically to
any other MongoDB instance.
.SH CONSIDERATIONS
.RS
.IP \(bu 2
Never change the name of the \fBmongos\f1 binary.
.IP \(bu 2
MongoDB disables support for TLS 1.0
encryption on systems where TLS 1.1+ is available.
.IP \(bu 2
The \fBmongos\f1\f1 binary cannot connect to \fBmongod\f1\f1
instances whose \fBfeature compatibility version (fCV)\f1 is greater
than that of the \fBmongos\f1\f1\&. For example, you cannot connect
a MongoDB 5.0 version \fBmongos\f1\f1 to a 7.0
sharded cluster with \fBfCV\f1 set to 7.0\&. You
can, however, connect a MongoDB 5.0 version
\fBmongos\f1\f1 to a 7.0 sharded cluster with \fBfCV\f1 set to 5.0\&.
.IP \(bu 2
\fBmongod\f1\f1 includes a \fBFull Time Diagnostic Data Capture\f1 mechanism to assist MongoDB engineers with troubleshooting
deployments. If this thread fails, it terminates the originating process.
To avoid the most common failures, confirm that the user running the
process has permissions to create the FTDC \fBdiagnostic.data\f1
directory. For \fBmongod\f1 the directory is within
\fBstorage.dbPath\f1\f1\&. For \fBmongos\f1 it is parallel to \fBsystemLog.path\f1\f1\&.
.RE
.SH OPTIONS
.PP
\fBConfiguration File Settings and Command\-Line Options Mapping\f1
.RS
.IP \(bu 2
MongoDB deprecates the SSL options and instead adds new
corresponding TLS options.
.IP \(bu 2
MongoDB adds
\fB\-\-tlsClusterCAFile\f1\f1/\fBnet.tls.clusterCAFile\f1\f1\&.
.RE
.RS
.IP \(bu 2
MongoDB 5.0 removes the \fB\-\-serviceExecutor\f1 command\-line option and the
corresponding \fBnet.serviceExecutor\f1 configuration option.
.RE
.SS CORE OPTIONS
.PP
\fBmongos \-\-help\f1, \fBmongos \-h\f1
.RS
.PP
Returns information on the options and use of \fBmongos\f1\&.
.RE
.PP
\fBmongos \-\-version\f1
.RS
.PP
Returns the \fBmongos\f1 release number.
.RE
.PP
\fBmongos \-\-config\f1, \fBmongos \-f\f1
.RS
.PP
Specifies a configuration file for runtime configuration options. The
configuration file is the preferred method for runtime configuration of
\fBmongos\f1\&. The options are equivalent to the command\-line
configuration options. See \fBConfiguration File Options\f1 for
more information.
.PP
Ensure the configuration file uses ASCII encoding. The \fBmongos\f1
instance does not support configuration files with non\-ASCII encoding,
including UTF\-8.
.RE
.PP
\fBmongos \-\-configExpand\f1
.RS
.PP
\fIDefault\f1: none
.PP
Enables using \fBExpansion Directives\f1
in configuration files. Expansion directives allow you to set
externally sourced values for configuration file options.
.PP
\fB\-\-configExpand\f1\f1 supports the following expansion directives:
.RS
.IP \(bu 2
.RS
.IP \(bu 4
Value
.IP \(bu 4
Description
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBnone\f1
.IP \(bu 4
Default. \fBmongos\f1 does not expand expansion directives.
\fBmongos\f1 fails to start if any configuration file settings
use expansion directives.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBrest\f1
.IP \(bu 4
\fBmongos\f1 expands \fB__rest\f1 expansion directives when
parsing the configuration file.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBexec\f1
.IP \(bu 4
\fBmongos\f1 expands \fB__exec\f1 expansion directives when
parsing the configuration file.
.RE
.RE
.PP
You can specify multiple expansion directives as a comma\-separated
list, for example: \fBrest, exec\f1\&. If the configuration file contains
expansion directives not specified to \fB\-\-configExpand\f1\f1, the \fBmongos\f1
returns an error and terminates.
.PP
See \fBExternally Sourced Configuration File Values\f1 for configuration files
for more information on expansion directives.
.RE
.PP
\fBmongos \-\-verbose\f1, \fBmongos \-v\f1
.RS
.PP
Increases the amount of internal reporting returned on standard output
or in log files. Increase the verbosity with the \fB\-v\f1 form by
including the option multiple times, for example: \fB\-vvvvv\f1\&.
.RE
.PP
\fBmongos \-\-quiet\f1
.RS
.PP
Runs \fBmongos\f1 in a quiet mode that attempts to limit the amount
of output.
.PP
This option suppresses:
.RS
.IP \(bu 2
output from \fBdatabase commands\f1
.IP \(bu 2
replication activity
.IP \(bu 2
connection accepted events
.IP \(bu 2
connection closed events
.RE
.RE
.PP
\fBmongos \-\-port\f1
.RS
.PP
\fIDefault\f1: 27017
.PP
The TCP port on which the \fBmongos\f1 instance listens for
client connections.
.PP
The \fB\-\-port\f1 option accepts a range of values between \fB0\f1 and \fB65535\f1\&.
Setting the port to \fB0\f1 configures \fBmongos\f1 to use an arbitrary port
assigned by the operating system.
.RE
.PP
\fBmongos \-\-bind_ip\f1
.RS
.PP
\fIDefault\f1: localhost
.PP
The hostnames and/or IP addresses and/or full Unix domain socket
paths on which \fBmongos\f1 should listen for client connections. You
may attach \fBmongos\f1 to any interface. To bind to multiple
addresses, enter a list of comma\-separated values.
.PP
You can specify both IPv4 and IPv6 addresses, or hostnames that
resolve to an IPv4 or IPv6 address.
.PP
If specifying an IPv6 address \fIor\f1 a hostname that resolves to an
IPv6 address to \fB\-\-bind_ip\f1\f1, you must start \fBmongos\f1 with
\fB\-\-ipv6\f1\f1 to enable IPv6 support. Specifying an IPv6 address
to \fB\-\-bind_ip\f1\f1 does not enable IPv6 support.
.PP
If specifying a
link\-local IPv6 address (https://en.wikipedia.org/wiki/Link\-local_address#IPv6)
(\fBfe80::/10\f1), you must append the
zone index (https://en.wikipedia.org/wiki/IPv6_address#Scoped_literal_IPv6_addresses_(with_zone_index))
to that address (i.e. \fBfe80::<address>%<adapter\-name>\f1).
.PP
To avoid configuration updates due to IP address changes, use DNS
hostnames instead of IP addresses. It is particularly important to
use a DNS hostname instead of an IP address when configuring replica
set members or sharded cluster members.
.PP
Use hostnames instead of IP addresses to configure clusters across a
split network horizon. Starting in MongoDB 5.0, nodes that are only
configured with an IP address fail startup validation and do not start.
.PP
Before you bind your instance to a publicly\-accessible IP address,
you must secure your cluster from unauthorized access. For a complete
list of security recommendations, see
\fBSecurity Checklist\f1\&. At minimum, consider
\fBenabling authentication\f1 and \fBhardening
network infrastructure\f1\&.
.PP
For more information about IP Binding, refer to the
\fBIP Binding\f1 documentation.
.PP
To bind to all IPv4 addresses, enter \fB0.0.0.0\f1\&.
.PP
To bind to all IPv4 and IPv6 addresses, enter \fB::,0.0.0.0\f1 or
an asterisk \fB"*"\f1 (enclose the asterisk in quotes to avoid filename pattern
expansion). Alternatively, use the \fBnet.bindIpAll\f1\f1 setting.
.RS
.IP \(bu 2
\fB\-\-bind_ip\f1 and \fB\-\-bind_ip_all\f1 are mutually exclusive.
Specifying both options causes \fBmongos\f1 to throw an error and
terminate.
.IP \(bu 2
The command\-line option \fB\-\-bind\f1 overrides the configuration
file setting \fBnet.bindIp\f1\f1\&.
.RE
.RE
.PP
\fBmongos \-\-bind_ip_all\f1
.RS
.PP
If specified, the \fBmongos\f1 instance binds to all IPv4
addresses (i.e. \fB0.0.0.0\f1). If \fBmongos\f1 starts with
\fB\-\-ipv6\f1\f1, \fB\-\-bind_ip_all\f1\f1 also binds to all IPv6 addresses
(i.e. \fB::\f1).
.PP
\fBmongos\f1 only supports IPv6 if started with \fB\-\-ipv6\f1\f1\&. Specifying
\fB\-\-bind_ip_all\f1\f1 alone does not enable IPv6 support.
.PP
Before you bind your instance to a publicly\-accessible IP address,
you must secure your cluster from unauthorized access. For a complete
list of security recommendations, see
\fBSecurity Checklist\f1\&. At minimum, consider
\fBenabling authentication\f1 and \fBhardening
network infrastructure\f1\&.
.PP
For more information about IP Binding, refer to the
\fBIP Binding\f1 documentation.
.PP
Alternatively, you can set the \fB\-\-bind_ip\f1 option to \fB::,0.0.0.0\f1
or to an asterisk \fB"*"\f1 (enclose the asterisk in quotes to avoid filename
pattern expansion).
.PP
\fB\-\-bind_ip\f1 and \fB\-\-bind_ip_all\f1 are mutually exclusive. That
is, you can specify one or the other, but not both.
.RE
.PP
\fBmongos \-\-listenBacklog\f1
.RS
.PP
\fIDefault\f1: Target system \fBSOMAXCONN\f1 constant
.PP
The maximum number of connections that can exist in the listen
queue.
.PP
Consult your local system\(aqs documentation to understand the
limitations and configuration requirements before using this
parameter.
.PP
To prevent undefined behavior, specify a value for this
parameter between \fB1\f1 and the local system \fBSOMAXCONN\f1
constant.
.PP
The default value for the \fBlistenBacklog\f1 parameter is set at
compile time to the target system \fBSOMAXCONN\f1 constant.
\fBSOMAXCONN\f1 is the maximum valid value that is documented for
the \fIbacklog\f1 parameter to the \fIlisten\f1 system call.
.PP
Some systems may interpret \fBSOMAXCONN\f1 symbolically, and others
numerically. The actual \fIlisten backlog\f1 applied in practice may
differ from any numeric interpretation of the \fBSOMAXCONN\f1 constant
or argument to \fB\-\-listenBacklog\f1, and may also be constrained by
system settings like \fBnet.core.somaxconn\f1 on Linux.
.PP
Passing a value for the \fBlistenBacklog\f1 parameter that exceeds the
\fBSOMAXCONN\f1 constant for the local system is, by the letter of the
standards, undefined behavior. Higher values may be silently integer
truncated, may be ignored, may cause unexpected resource
consumption, or have other adverse consequences.
.PP
On systems with workloads that exhibit connection spikes, for which
it is empirically known that the local system can honor higher
values for the \fIbacklog\f1 parameter than the \fBSOMAXCONN\f1 constant,
setting the \fBlistenBacklog\f1 parameter to a higher value may reduce
operation latency as observed by the client by reducing the number
of connections which are forced into a backoff state.
.RE
.PP
\fBmongos \-\-maxConns\f1
.RS
.PP
The maximum number of simultaneous connections that \fBmongos\f1
accepts. This setting has no effect if it is higher than your
operating system\(aqs configured maximum connection tracking threshold.
.PP
Do not assign too low of a value to this option, or you will
encounter errors during normal application operation.
.PP
This is particularly useful for a \fBmongos\f1\f1 if you have a client
that creates multiple connections and allows them to timeout rather
than closing them.
.PP
In this case, set \fBmaxIncomingConnections\f1\f1 to a value slightly
higher than the maximum number of connections that the client creates, or the
maximum size of the connection pool.
.PP
This setting prevents the \fBmongos\f1\f1 from causing connection spikes on
the individual \fBshards\f1\&. Spikes like these may disrupt the
operation and memory allocation of the \fBsharded cluster\f1\&.
.RE
.PP
\fBmongos \-\-logpath\f1
.RS
.PP
Sends all diagnostic logging information to a log file instead of to
standard output or to the host\(aqs \fBsyslog\f1 system. MongoDB creates
the log file at the path you specify.
.PP
By default, MongoDB will move any existing log file rather than overwrite
it. To instead append to the log file, set the \fB\-\-logappend\f1\f1 option.
.RE
.PP
\fBmongos \-\-syslog\f1
.RS
.PP
Sends all logging output to the host\(aqs \fBsyslog\f1 system rather
than to standard output or to a log file (\fB\-\-logpath\f1\f1).
.PP
The \fB\-\-syslog\f1\f1 option is not supported on Windows.
.PP
The \fBsyslog\f1 daemon generates timestamps when it logs a message, not
when MongoDB issues the message. This can lead to misleading timestamps
for log entries, especially when the system is under heavy load. We
recommend using the \fB\-\-logpath\f1\f1 option for production systems to
ensure accurate timestamps.
.PP
MongoDB includes the \fBcomponent\f1 in its log
messages to \fBsyslog\f1\&.
.PP
.EX
  ...  ACCESS   [repl writer worker 5] Unsupported modification to roles collection ...
.EE
.RE
.PP
\fBmongos \-\-syslogFacility\f1
.RS
.PP
\fIDefault\f1: user
.PP
Specifies the facility level used when logging messages to syslog.
The value you specify must be supported by your
operating system\(aqs implementation of syslog. To use this option, you
must  enable the \fB\-\-syslog\f1\f1 option.
.RE
.PP
\fBmongos \-\-logappend\f1
.RS
.PP
Appends new entries to the end of the existing log file when the \fBmongos\f1
instance restarts. Without this option, \fBmongod\f1\f1 will back up the
existing log and create a new file.
.RE
.PP
\fBmongos \-\-logRotate\f1
.RS
.PP
\fIDefault\f1: rename
.PP
Determines the behavior for the \fBlogRotate\f1\f1 command when
rotating the server log and/or the audit log. Specify either
\fBrename\f1 or \fBreopen\f1:
.RS
.IP \(bu 2
\fBrename\f1 renames the log file.
.IP \(bu 2
\fBreopen\f1 closes and reopens the log file following the typical
Linux/Unix log rotate behavior. Use \fBreopen\f1 when using the
Linux/Unix logrotate utility to avoid log loss.
.IP
If you specify \fBreopen\f1, you must also use \fB\-\-logappend\f1\f1\&.
.RE
.RE
.PP
\fBmongos \-\-redactClientLogData\f1
.RS
.PP
\fIAvailable in MongoDB Enterprise only.\f1
.PP
A \fBmongos\f1 running with \fB\-\-redactClientLogData\f1\f1 redacts any message accompanying a given
log event before logging. This prevents the \fBmongos\f1 from writing
potentially sensitive data stored on the database to the diagnostic log.
Metadata such as error or operation codes, line numbers, and source file
names are still visible in the logs.
.PP
Use \fB\-\-redactClientLogData\f1\f1 in conjunction with
\fBEncryption at Rest\f1 and
\fBTLS/SSL (Transport Encryption)\f1 to assist compliance with
regulatory requirements.
.PP
For example, a MongoDB deployment might store Personally Identifiable
Information (PII) in one or more collections. The \fBmongos\f1 logs events
such as those related to CRUD operations, sharding metadata, etc. It is
possible that the \fBmongos\f1 may expose PII as a part of these logging
operations. A \fBmongos\f1 running with \fB\-\-redactClientLogData\f1\f1 removes any message
accompanying these events before being output to the log, effectively
removing the PII.
.PP
Diagnostics on a \fBmongos\f1 running with \fB\-\-redactClientLogData\f1\f1 may be more difficult
due to the lack of data related to a log event. See the
\fBprocess logging\f1 manual page for an
example of the effect of \fB\-\-redactClientLogData\f1\f1 on log output.
.PP
On a running \fBmongos\f1, use \fBsetParameter\f1\f1 with the
\fBredactClientLogData\f1\f1 parameter to configure this setting.
.RE
.PP
\fBmongos \-\-timeStampFormat\f1
.RS
.PP
\fIDefault\f1: iso8601\-local
.PP
The time format for timestamps in log messages. Specify one of the
following values:
.RS
.IP \(bu 2
.RS
.IP \(bu 4
Value
.IP \(bu 4
Description
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBiso8601\-utc\f1
.IP \(bu 4
Displays timestamps in Coordinated Universal Time (UTC) in the
ISO\-8601 format. For example, for New York at the start of the
Epoch: \fB1970\-01\-01T00:00:00.000Z\f1
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBiso8601\-local\f1
.IP \(bu 4
Displays timestamps in local time in the ISO\-8601
format. For example, for New York at the start of the Epoch:
\fB1969\-12\-31T19:00:00.000\-05:00\f1
.RE
.RE
.PP
\fB\-\-timeStampFormat\f1\f1 no longer supports \fBctime\f1\&. An example of \fBctime\f1
formatted date is: \fBWed Dec 31 18:17:54.811\f1\&.
.RE
.PP
\fBmongos \-\-pidfilepath\f1
.RS
.PP
Specifies a file location to store the process ID (PID) of the \fBmongos\f1
process. The user running the \fBmongod\f1 or \fBmongos\f1
process must be able to write to this path. If the \fB\-\-pidfilepath\f1\f1 option is not
specified, the process does not create a PID file. This option is generally
only useful in combination with the \fB\-\-fork\f1\f1 option.
.PP
On Linux, PID file management is generally the responsibility of
your distro\(aqs init system: usually a service file in the \fB/etc/init.d\f1
directory, or a systemd unit file registered with \fBsystemctl\f1\&. Only
use the \fB\-\-pidfilepath\f1\f1 option if you are not using one of these init
systems. For more information, please see the respective
\fBInstallation Guide\f1 for your operating system.
.PP
On macOS, PID file management is generally handled by \fBbrew\f1\&. Only use
the \fB\-\-pidfilepath\f1\f1 option if you are not using \fBbrew\f1 on your macOS system.
For more information, please see the respective
Installation Guide for your operating system.
.RE
.PP
\fBmongos \-\-keyFile\f1
.RS
.PP
Specifies the path to a key file that stores the shared secret
that MongoDB instances use to authenticate to each other in a
\fBsharded cluster\f1 or \fBreplica set\f1\&. \fB\-\-keyFile\f1\f1 implies
\fBclient authorization\f1\&. See \fBInternal/Membership Authentication\f1 for more
information.
.PP
\fBKeyfiles for internal membership authentication\f1 use YAML format to allow for multiple keys in a
keyfile. The YAML format accepts either:
.RS
.IP \(bu 2
A single key string (same as in earlier versions)
.IP \(bu 2
A sequence of key strings
.RE
.PP
The YAML format is compatible with the existing single\-key
keyfiles that use the text file format.
.RE
.PP
\fBmongos \-\-setParameter\f1
.RS
.PP
Specifies one of the MongoDB parameters described in
\fBMongoDB Server Parameters\f1\&. You can specify multiple \fBsetParameter\f1
fields.
.RE
.PP
\fBmongos \-\-noscripting\f1
.RS
.PP
Disables the scripting engine.  When disabled, you cannot use
operations that perform server\-side execution of JavaScript code,
such as the \fB$where\f1\f1 query operator, \fBmapReduce\f1\f1
command, \fB$accumulator\f1\f1, and \fB$function\f1\f1\&.
.PP
If you do not use these operations, disable server\-side scripting.
.RE
.PP
\fBmongos \-\-nounixsocket\f1
.RS
.PP
Disables listening on the UNIX domain socket. \fB\-\-nounixsocket\f1\f1 applies only
to Unix\-based systems.
.PP
The \fBmongos\f1 process
always listens on the UNIX socket unless one of the following is true:
.RS
.IP \(bu 2
\fB\-\-nounixsocket\f1\f1 is set
.IP \(bu 2
\fBnet.bindIp\f1\f1 is not set
.IP \(bu 2
\fBnet.bindIp\f1\f1 does not specify \fBlocalhost\f1 or its associated IP address
.RE
.PP
\fBmongos\f1 installed from official \fB\&.deb\f1 and \fB\&.rpm\f1 packages
have the \fBbind_ip\f1 configuration set to \fB127.0.0.1\f1 by
default.
.RE
.PP
\fBmongos \-\-unixSocketPrefix\f1
.RS
.PP
\fIDefault\f1: /tmp
.PP
The path for the UNIX socket. \fB\-\-unixSocketPrefix\f1\f1 applies only
to Unix\-based systems.
.PP
If this option has no value, the
\fBmongos\f1 process creates a socket with \fB/tmp\f1 as a prefix. MongoDB
creates and listens on a UNIX socket unless one of the following is true:
.RS
.IP \(bu 2
\fBnet.unixDomainSocket.enabled\f1\f1 is \fBfalse\f1
.IP \(bu 2
\fB\-\-nounixsocket\f1\f1 is set
.IP \(bu 2
\fBnet.bindIp\f1\f1 is not set
.IP \(bu 2
\fBnet.bindIp\f1\f1 does not specify \fBlocalhost\f1 or its associated IP address
.RE
.RE
.PP
\fBmongos \-\-filePermissions\f1
.RS
.PP
\fIDefault\f1: \fB0700\f1
.PP
Sets the permission for the UNIX domain socket file.
.PP
\fB\-\-filePermissions\f1\f1 applies only to Unix\-based systems.
.RE
.PP
\fBmongos \-\-fork\f1
.RS
.PP
Enables a \fBdaemon\f1 mode that runs the \fBmongos\f1 process in the
background. The \fB\-\-fork\f1\f1 option is not supported on Windows.
.PP
By default \fBmongos\f1 does not run as a daemon. You run \fBmongos\f1 as
a daemon by using either \fB\-\-fork\f1\f1 or a controlling process
that handles daemonization, such as \fBupstart\f1 or \fBsystemd\f1\&.
.PP
Using the \fB\-\-fork\f1\f1 option requires that you configure log
output for the \fBmongos\f1 with one of the following:
.RS
.IP \(bu 2
\fB\-\-logpath\f1\f1
.IP \(bu 2
\fB\-\-syslog\f1\f1
.RE
.RE
.PP
\fBmongos \-\-transitionToAuth\f1
.RS
.PP
Allows the \fBmongos\f1 to accept and create authenticated and
non\-authenticated connections to and from other \fBmongod\f1\f1
and \fBmongos\f1 instances in the deployment. Used for
performing rolling transition of replica sets or sharded clusters
from a no\-auth configuration to \fBinternal authentication\f1\&. Requires specifying a \fBinternal
authentication\f1 mechanism such as
\fB\-\-keyFile\f1\f1\&.
.PP
For example, if using \fBkeyfiles\f1 for
\fBinternal authentication\f1, the \fBmongos\f1 creates
an authenticated connection with any \fBmongod\f1\f1 or \fBmongos\f1
in the deployment using a matching keyfile. If the security mechanisms do
not match, the \fBmongos\f1 utilizes a non\-authenticated connection instead.
.PP
A \fBmongos\f1 running with \fB\-\-transitionToAuth\f1\f1 does not enforce \fBuser access
controls\f1\&. Users may connect to your deployment without any
access control checks and perform read, write, and administrative operations.
.PP
A \fBmongos\f1 running with \fBinternal authentication\f1 and \fIwithout\f1 \fB\-\-transitionToAuth\f1\f1 requires clients to connect
using \fBuser access controls\f1\&. Update clients to
connect to the \fBmongos\f1 using the appropriate \fBuser\f1
prior to restarting \fBmongos\f1 without \fB\-\-transitionToAuth\f1\f1\&.
.RE
.PP
\fBmongos \-\-networkMessageCompressors\f1
.RS
.PP
\fIDefault\f1: snappy,zstd,zlib
.PP
Specifies the default compressor(s) to use for
communication between this \fBmongos\f1 instance and:
.RS
.IP \(bu 2
other members of the sharded cluster
.IP \(bu 2
\fBmongosh\f1\f1
.IP \(bu 2
drivers that support the \fBOP_COMPRESSED\f1 message format.
.RE
.PP
MongoDB supports the following compressors:
.RS
.IP \(bu 2
\fBsnappy\f1
.IP \(bu 2
\fBzlib\f1
.IP \(bu 2
\fBzstd\f1
.RE
.PP
Both \fBmongod\f1\f1 and \fBmongos\f1 instances
default to \fBsnappy,zstd,zlib\f1 compressors, in that order.
.PP
To disable network compression, set the value to \fBdisabled\f1\&.
.PP
Messages are compressed when both parties enable network
compression. Otherwise, messages between the parties are
uncompressed.
.PP
If you specify multiple compressors, then the order in which you list
the compressors matter as well as the communication initiator. For
example, if \fBmongosh\f1\f1 specifies the following network
compressors \fBzlib,snappy\f1 and the \fBmongod\f1\f1 specifies
\fBsnappy,zlib\f1, messages between \fBmongosh\f1\f1 and
\fBmongod\f1\f1 uses \fBzlib\f1\&.
.PP
If the parties do not share at least one common compressor, messages
between the parties are uncompressed. For example, if
\fBmongosh\f1\f1 specifies the network compressor
\fBzlib\f1 and \fBmongod\f1\f1 specifies \fBsnappy\f1, messages
between \fBmongosh\f1\f1 and \fBmongod\f1\f1 are not
compressed.
.RE
.PP
\fBmongos \-\-timeZoneInfo\f1
.RS
.PP
The full path from which to load the time zone database. If this option
is not provided, then MongoDB uses its built\-in time zone database.
.PP
The configuration file included with Linux and macOS packages sets the
time zone database path to \fB/usr/share/zoneinfo\f1 by default.
.PP
The built\-in time zone database is a copy of the Olson/IANA time zone
database (https://www.iana.org/time\-zones)\&. It is updated along with
MongoDB releases, but the time zone database release cycle
differs from the MongoDB release cycle. The most recent release of
the time zone database is available on our download site (https://downloads.mongodb.org/olson_tz_db/timezonedb\-latest.zip)\&.
.PP
.EX
  wget https://downloads.mongodb.org/olson_tz_db/timezonedb\-latest.zip
  unzip timezonedb\-latest.zip
  mongos \-\-timeZoneInfo timezonedb\-2017b/
.EE
.PP
MongoDB uses the third party timelib (https://github.com/derickr/timelib) library to provide accurate
conversions between timezones. Due to a recent update, \fBtimelib\f1
could create inaccurate time zone conversions in older versions of
MongoDB.
.PP
To explicitly link to the time zone database in versions of MongoDB
prior to 5.0, download the time zone database (https://downloads.mongodb.org/olson_tz_db/timezonedb\-latest.zip)\&.
and use the \fBtimeZoneInfo\f1\f1 parameter.
.RE
.PP
\fBmongos \-\-outputConfig\f1
.RS
.PP
Outputs the \fBmongos\f1 instance\(aqs configuration options, formatted
in YAML, to \fBstdout\f1 and exits the \fBmongos\f1 instance. For
configuration options that uses \fBExternally Sourced Configuration File Values\f1,
\fB\-\-outputConfig\f1\f1 returns the resolved value for those options.
.PP
This may include any configured passwords or secrets previously
obfuscated through the external source.
.PP
For usage examples, see:
.RS
.IP \(bu 2
\fBOutput the Configuration File with Resolved Expansion Directive Values\f1
.IP \(bu 2
\fBConvert Command\-Line Options to YAML\f1
.RE
.RE
.SS SHARDED CLUSTER OPTIONS
.PP
\fBmongos \-\-configdb\f1
.RS
.PP
Specifies the \fBconfiguration servers\f1 for the
\fBsharded cluster\f1\&.
.PP
Config servers for sharded clusters are
deployed as a \fBreplica set\f1\&. The
replica set config servers must run the \fBWiredTiger storage engine\f1\&.
.PP
Specify the config server replica set name and the hostname and port of
at least one of the members of the config server replica set.
.PP
.EX
  sharding:
    configDB: <configReplSetName>/cfg1.example.net:27019, cfg2.example.net:27019,...
.EE
.PP
The \fBmongos\f1 instances for the sharded cluster must specify
the same config server replica set name but can specify hostname and
port of different members of the replica set.
.RE
.PP
\fBmongos \-\-localThreshold\f1
.RS
.PP
\fIDefault\f1: 15
.PP
Specifies the ping time, in milliseconds, that \fBmongos\f1 uses
to determine which secondary replica set members to pass read
operations from clients. The default value of \fB15\f1 corresponds to
the default value in all of the client drivers (https://www.mongodb.com/docs/drivers/)\&.
.PP
When \fBmongos\f1 receives a request that permits reads to
\fBsecondary\f1 members, it:
.RS
.IP \(bu 2
Finds the member of the set with the lowest ping time.
.IP \(bu 2
Constructs a list of replica set members that is within a ping time of
15 milliseconds of the nearest suitable member of the set.
.IP
If you specify a value for the \fB\-\-localThreshold\f1\f1 option,
\fBmongos\f1 constructs the list of replica members that are within
the latency allowed by this value.
.IP \(bu 2
Selects a member to read from at random from this list.
.RE
.PP
The ping time used for a member compared by the \fB\-\-localThreshold\f1\f1 setting is a
moving average of recent ping times, calculated at most every 10
seconds. As a result, some queries may reach members above the threshold
until the \fBmongos\f1 recalculates the average.
.PP
See the \fBRead Preference for Replica Sets\f1
section of the \fBread preference\f1
documentation for more information.
.RE
.SS TLS OPTIONS
.PP
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 for full documentation of MongoDB\(aqs
support.
.PP
\fBmongos \-\-tlsMode\f1
.RS
.PP
Enables TLS used for all network connections. The
argument to the \fB\-\-tlsMode\f1\f1 option can be one of the following:
.RS
.IP \(bu 2
.RS
.IP \(bu 4
Value
.IP \(bu 4
Description
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBdisabled\f1
.IP \(bu 4
The server does not use TLS.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBallowTLS\f1
.IP \(bu 4
Connections between servers do not use TLS. For incoming
connections, the server accepts both TLS and non\-TLS.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBpreferTLS\f1
.IP \(bu 4
Connections between servers use TLS. For incoming
connections, the server accepts both TLS and non\-TLS.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBrequireTLS\f1
.IP \(bu 4
The server uses and accepts only TLS encrypted connections.
.RE
.RE
.PP
If \fB\-\-tlsCAFile\f1 or \fBtls.CAFile\f1 is not
specified and you are not using x.509 authentication, you must set the
\fBtlsUseSystemCA\f1\f1 parameter to \fBtrue\f1\&. This makes MongoDB use
the system\-wide CA certificate store when connecting to a TLS\-enabled server.
.PP
If using x.509 authentication, \fB\-\-tlsCAFile\f1 or \fBtls.CAFile\f1
must be specified unless using \fB\-\-tlsCertificateSelector\f1\f1\&.
.PP
For more information about TLS and MongoDB, see
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 and
\fBTLS/SSL Configuration for Clients\f1 .
.RE
.PP
\fBmongos \-\-tlsCertificateKeyFile\f1
.RS
.PP
On macOS or Windows, you can use a certificate from
the operating system\(aqs secure store instead of specifying a PEM file. See
\fB\-\-tlsCertificateSelector\f1\f1\&.
.PP
Specifies the \&.pem file that contains both the TLS certificate
and key.
.RS
.IP \(bu 2
On Linux/BSD, you must specify \fB\-\-tlsCertificateKeyFile\f1\f1 when TLS is enabled.
.IP \(bu 2
On Windows or macOS, you must specify either \fB\-\-tlsCertificateKeyFile\f1\f1 or
\fB\-\-tlsCertificateSelector\f1\f1 when TLS is enabled.
.RE
.PP
For more information about TLS and MongoDB, see
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 and
\fBTLS/SSL Configuration for Clients\f1 .
.RE
.PP
\fBmongos \-\-tlsCertificateKeyFilePassword\f1
.RS
.PP
Specifies the password to decrypt the certificate\-key file (i.e.
\fB\-\-tlsCertificateKeyFile\f1\f1). Use the \fB\-\-tlsCertificateKeyFilePassword\f1\f1 option only if the
certificate\-key file is encrypted. In all cases, the \fBmongos\f1
redacts the password from all logging and reporting output.
.RS
.IP \(bu 2
On Linux/BSD, if the private key in the PEM file is encrypted and
you do not specify the \fB\-\-tlsCertificateKeyFilePassword\f1\f1 option, MongoDB prompts for a
passphrase. See \fBTLS/SSL Certificate Passphrase\f1\&.
.IP \(bu 2
On macOS or Windows, if the private key in the PEM file is
encrypted, you must explicitly specify the \fB\-\-tlsCertificateKeyFilePassword\f1\f1 option.
Alternatively, you can use a certificate from the secure system
store (see \fB\-\-tlsCertificateSelector\f1\f1) instead of a PEM file or use an
unencrypted PEM file.
.RE
.PP
For more information about TLS and MongoDB, see
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 and
\fBTLS/SSL Configuration for Clients\f1 .
.RE
.PP
\fBmongos \-\-clusterAuthMode\f1
.RS
.PP
\fIDefault\f1: keyFile
.PP
The authentication mode used for cluster authentication. If you use
\fBinternal x.509 authentication\f1,
specify so here. This option can have one of the following values:
.RS
.IP \(bu 2
.RS
.IP \(bu 4
Value
.IP \(bu 4
Description
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBkeyFile\f1
.IP \(bu 4
Use a keyfile for authentication.
Accept only keyfiles.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBsendKeyFile\f1
.IP \(bu 4
For rolling upgrade purposes. Send a keyfile for
authentication but can accept both keyfiles and x.509
certificates.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBsendX509\f1
.IP \(bu 4
For rolling upgrade purposes. Send the x.509 certificate for
authentication but can accept both keyfiles and x.509
certificates.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBx509\f1
.IP \(bu 4
Recommended. Send the x.509 certificate for authentication and
accept only x.509 certificates.
.RE
.RE
.PP
If \fB\-\-tlsCAFile\f1 or \fBtls.CAFile\f1 is not
specified and you are not using x.509 authentication, you must set the
\fBtlsUseSystemCA\f1\f1 parameter to \fBtrue\f1\&. This makes MongoDB use
the system\-wide CA certificate store when connecting to a TLS\-enabled server.
.PP
If using x.509 authentication, \fB\-\-tlsCAFile\f1 or \fBtls.CAFile\f1
must be specified unless using \fB\-\-tlsCertificateSelector\f1\f1\&.
.PP
For more information about TLS and MongoDB, see
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 and
\fBTLS/SSL Configuration for Clients\f1 .
.RE
.PP
\fBmongos \-\-tlsClusterFile\f1
.RS
.PP
On macOS or Windows, you can use a certificate
from the operating system\(aqs secure store instead of a PEM
file. See \fB\-\-tlsClusterCertificateSelector\f1\f1\&.
.PP
Specifies the \&.pem file that contains the x.509 certificate\-key
file for \fBmembership authentication\f1
for the cluster or replica set.
.PP
If \fB\-\-tlsClusterFile\f1\f1 does not specify the \fB\&.pem\f1 file for internal cluster
authentication or the alternative
\fB\-\-tlsClusterCertificateSelector\f1\f1, the cluster uses the
\fB\&.pem\f1 file specified in the \fB\-\-tlsCertificateKeyFile\f1\f1 option or
the certificate returned by the \fB\-\-tlsCertificateSelector\f1\f1\&.
.PP
If using x.509 authentication, \fB\-\-tlsCAFile\f1 or \fBtls.CAFile\f1
must be specified unless using \fB\-\-tlsCertificateSelector\f1\f1\&.
.PP
\fBmongod\f1\f1 / \fBmongos\f1\f1 logs a warning on
connection if the presented x.509 certificate expires within \fB30\f1
days of the \fBmongod/mongos\f1 host system time. See
\fBx.509 Certificates Nearing Expiry Trigger Warnings\f1 for more
information.
.PP
For more information about TLS and MongoDB, see
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 and
\fBTLS/SSL Configuration for Clients\f1 .
.RE
.PP
\fBmongos \-\-tlsClusterPassword\f1
.RS
.PP
Specifies the password to decrypt the x.509 certificate\-key file
specified with \fB\-\-tlsClusterFile\f1\&. Use the \fB\-\-tlsClusterPassword\f1\f1 option only
if the certificate\-key file is encrypted. In all cases, the \fBmongos\f1
redacts the password from all logging and reporting output.
.RS
.IP \(bu 2
On Linux/BSD, if the private key in the x.509 file is encrypted and
you do not specify the \fB\-\-tlsClusterPassword\f1\f1 option, MongoDB prompts for a
passphrase. See \fBTLS/SSL Certificate Passphrase\f1\&.
.IP \(bu 2
On macOS or Windows, if the private key in the x.509 file is
encrypted, you must explicitly specify the \fB\-\-tlsClusterPassword\f1\f1 option.
Alternatively, you can either use a certificate from the secure
system store (see \fB\-\-tlsClusterCertificateSelector\f1\f1) instead of a cluster PEM file or
use an unencrypted PEM file.
.RE
.PP
For more information about TLS and MongoDB, see
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 and
\fBTLS/SSL Configuration for Clients\f1 .
.RE
.PP
\fBmongos \-\-tlsCAFile\f1
.RS
.PP
Specifies the \&.pem file that contains the root certificate chain
from the Certificate Authority. Specify the file name of the
\&.pem file using relative or absolute paths.
.PP
On macOS or Windows, you can use a certificate from
the operating system\(aqs secure store instead of a PEM key file. See
\fB\-\-tlsCertificateSelector\f1\f1\&. When using the secure store, you
do not need to, but can, also specify the \fB\-\-tlsCAFile\f1\f1\&.
.PP
For more information about TLS and MongoDB, see
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 and
\fBTLS/SSL Configuration for Clients\f1 .
.RE
.PP
\fBmongos \-\-tlsClusterCAFile\f1
.RS
.PP
Specifies the \&.pem file that contains the root certificate chain
from the Certificate Authority used to validate the certificate
presented by a client establishing a connection. Specify the file
name of the \&.pem file using relative or absolute paths.
.PP
If \fB\-\-tlsClusterCAFile\f1\f1 does not specify the \&.pem file for validating the
certificate from a client establishing a connection, the cluster uses
the \&.pem file specified in the \fB\-\-tlsCAFile\f1\f1 option.
.PP
\fB\-\-tlsClusterCAFile\f1\f1 lets you use separate Certificate Authorities to verify the
client to server and server to client portions of the TLS handshake.
.PP
On macOS or Windows, you can use a certificate from
the operating system\(aqs secure store instead of a PEM key file. See
\fB\-\-tlsClusterCertificateSelector\f1\f1\&. When using the secure store, you
do not need to, but can, also specify the \fB\-\-tlsClusterCAFile\f1\f1\&.
.PP
Requires that \fB\-\-tlsCAFile\f1\f1 is set.
.PP
For more information about TLS and MongoDB, see
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 and
\fBTLS/SSL Configuration for Clients\f1 .
.RE
.PP
\fBmongos \-\-tlsCertificateSelector\f1
.RS
.PP
Available on Windows and macOS as an alternative to \fB\-\-tlsCertificateKeyFile\f1\f1\&.
.PP
The \fB\-\-tlsCertificateKeyFile\f1\f1 and \fB\-\-tlsCertificateSelector\f1\f1 options are mutually exclusive. You can only
specify one.
.PP
Specifies a certificate property in order to select a matching
certificate from the operating system\(aqs certificate store.
.PP
\fB\-\-tlsCertificateSelector\f1\f1 accepts an argument of the format \fB<property>=<value>\f1
where the property can be one of the following:
.RS
.IP \(bu 2
.RS
.IP \(bu 4
Property
.IP \(bu 4
Value type
.IP \(bu 4
Description
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBsubject\f1
.IP \(bu 4
ASCII string
.IP \(bu 4
Subject name or common name on certificate
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBthumbprint\f1
.IP \(bu 4
hex string
.IP \(bu 4
A sequence of bytes, expressed as hexadecimal, used to
identify a public key by its SHA\-1 digest.
.IP
The \fBthumbprint\f1 is sometimes referred to as a
\fBfingerprint\f1\&.
.RE
.RE
.PP
When using the system SSL certificate store, OCSP (Online
Certificate Status Protocol) is used to validate the revocation
status of certificates.
.PP
You cannot use the \fBrotateCertificates\f1\f1 command or the
\fBdb.rotateCertificates()\f1\f1 shell method when using
\fBnet.tls.certificateSelector\f1\f1 or
\fB\-\-tlsCertificateSelector\f1\f1
set to \fBthumbprint\f1
.RE
.PP
\fBmongos \-\-tlsClusterCertificateSelector\f1
.RS
.PP
Available on Windows and macOS as an alternative to
\fB\-\-tlsClusterFile\f1\f1\&.
.PP
\fB\-\-tlsClusterFile\f1\f1 and \fB\-\-tlsClusterCertificateSelector\f1\f1 options are mutually exclusive. You can only
specify one.
.PP
Specifies a certificate property in order to select a matching
certificate from the operating system\(aqs certificate store to use for
internal authentication.
.PP
\fB\-\-tlsClusterCertificateSelector\f1\f1 accepts an argument of the format \fB<property>=<value>\f1
where the property can be one of the following:
.RS
.IP \(bu 2
.RS
.IP \(bu 4
Property
.IP \(bu 4
Value type
.IP \(bu 4
Description
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBsubject\f1
.IP \(bu 4
ASCII string
.IP \(bu 4
Subject name or common name on certificate
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBthumbprint\f1
.IP \(bu 4
hex string
.IP \(bu 4
A sequence of bytes, expressed as hexadecimal, used to
identify a public key by its SHA\-1 digest.
.IP
The \fBthumbprint\f1 is sometimes referred to as a
\fBfingerprint\f1\&.
.RE
.RE
.PP
\fBmongod\f1\f1 / \fBmongos\f1\f1 logs a warning on
connection if the presented x.509 certificate expires within \fB30\f1
days of the \fBmongod/mongos\f1 host system time. See
\fBx.509 Certificates Nearing Expiry Trigger Warnings\f1 for more
information.
.RE
.PP
\fBmongos \-\-tlsCRLFile\f1
.RS
.PP
Specifies the \&.pem file that contains the Certificate Revocation
List. Specify the file name of the \&.pem file using relative or
absolute paths.
.RS
.IP \(bu 2
You cannot specify a CRL file on
macOS. Instead, you can use the system SSL certificate store,
which uses OCSP (Online Certificate Status Protocol) to
validate the revocation status of certificates. To use the
system SSL certificate store, see
\fB\-\-tlsCertificateSelector\f1\f1\&.
.IP \(bu 2
To check for certificate revocation,
MongoDB \fBenables\f1\f1 the use of OCSP
(Online Certificate Status Protocol) by default as an
alternative to specifying a CRL file or using the system SSL
certificate store.
.RE
.PP
For more information about TLS and MongoDB, see
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 and
\fBTLS/SSL Configuration for Clients\f1 .
.RE
.PP
\fBmongos \-\-tlsAllowConnectionsWithoutCertificates\f1
.RS
.PP
By default, the server bypasses client certificate validation unless
the server is configured to use a CA file. If a CA file is provided, the
following rules apply:
.RS
.IP \(bu 2
For clients that don\(aqt provide certificates, \fBmongod\f1\f1 or
\fBmongos\f1\f1 encrypts the TLS/SSL connection, assuming the
connection is successfully made.
.IP \(bu 2
For clients that present a certificate, \fBmongos\f1 performs
certificate validation using the root certificate chain specified by
\fB\-\-tlsCAFile\f1\f1  and reject clients with invalid
certificates.
.RE
.PP
Use the \fB\-\-tlsAllowConnectionsWithoutCertificates\f1\f1 option if you have
a mixed deployment that includes clients that do not or cannot present
certificates to the \fBmongos\f1\&.
.PP
For more information about TLS and MongoDB, see
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 and
\fBTLS/SSL Configuration for Clients\f1 .
.RE
.PP
\fBmongos \-\-tlsAllowInvalidCertificates\f1
.RS
.PP
Bypasses the validation checks for TLS certificates on other
servers in the cluster and allows the use of invalid certificates to
connect.
.PP
If you specify
\fB\-\-tlsAllowInvalidCertificates\f1 or \fBtls.allowInvalidCertificates:
true\f1 when using x.509 authentication, an invalid certificate is
only sufficient to establish a TLS connection but is
\fIinsufficient\f1 for authentication.
.PP
When using
the \fB\-\-tlsAllowInvalidCertificates\f1\f1 setting, MongoDB
logs a warning regarding the use of the invalid certificate.
.PP
For more information about TLS and MongoDB, see
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 and
\fBTLS/SSL Configuration for Clients\f1 .
.RE
.PP
\fBmongos \-\-tlsAllowInvalidHostnames\f1
.RS
.PP
Disables the validation of the hostnames in TLS certificates,
when connecting to other members of the replica set or sharded cluster
for inter\-process authentication. This allows \fBmongos\f1 to connect
to other members if the hostnames in their certificates do not match
their configured hostname.
.PP
For more information about TLS and MongoDB, see
\fBConfigure mongod\f1 and mongos\f1 for TLS/SSL\f1 and
\fBTLS/SSL Configuration for Clients\f1 .
.RE
.PP
\fBmongos \-\-tlsDisabledProtocols\f1
.RS
.PP
Prevents a MongoDB server running with TLS from accepting
incoming connections that use a specific protocol or protocols. To
specify multiple protocols, use a comma separated list of protocols.
.PP
\fB\-\-tlsDisabledProtocols\f1\f1 recognizes the following protocols: \fBTLS1_0\f1, \fBTLS1_1\f1,
\fBTLS1_2\f1, and \fBTLS1_3\f1\&.
.RS
.IP \(bu 2
On macOS, you cannot disable \fBTLS1_1\f1 and leave both \fBTLS1_0\f1 and
\fBTLS1_2\f1 enabled. You must disable at least one of the other
two, for example, \fBTLS1_0,TLS1_1\f1\&.
.IP \(bu 2
To list multiple protocols, specify as a comma separated list of
protocols. For example \fBTLS1_0,TLS1_1\f1\&.
.IP \(bu 2
Specifying an unrecognized protocol prevents the server from
starting.
.IP \(bu 2
The specified disabled protocols overrides any default disabled
protocols.
.RE
.PP
MongoDB disables the use of TLS 1.0 if TLS
1.1+ is available on the system. To enable the disabled TLS 1.0,
specify \fBnone\f1 to \fB\-\-tlsDisabledProtocols\f1\f1\&.
.PP
Members of replica sets and sharded clusters must speak at least one
protocol in common.
.PP
\fBDisallow Protocols\f1
.RE
.PP
\fBmongos \-\-tlsFIPSMode\f1
.RS
.PP
Directs the \fBmongos\f1 to use the FIPS mode of the  TLS
library. Your system must have a FIPS
compliant library to use the \fB\-\-tlsFIPSMode\f1\f1 option.
.PP
FIPS\-compatible TLS/SSL is
available only in MongoDB Enterprise (http://www.mongodb.com/products/mongodb\-enterprise\-advanced?tck=docs_server)\&. See
\fBConfigure MongoDB for FIPS\f1 for more information.
.RE
.SS AUDIT OPTIONS
.PP
\fBmongos \-\-auditCompressionMode\f1
.RS
.PP
Specifies the compression mode for \fBaudit log encryption\f1\&. You must also enable audit log
encryption using either \fB\-\-auditEncryptionKeyUID\f1\f1 or
\fB\-\-auditLocalKeyFile\f1\f1\&.
.PP
\fB\-\-auditCompressionMode\f1\f1 can be set to one of these values:
.RS
.IP \(bu 2
.RS
.IP \(bu 4
Value
.IP \(bu 4
Description
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBzstd\f1
.IP \(bu 4
Use the \fBzstd\f1 algorithm to compress the audit log.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBnone\f1 \fI(default)\f1
.IP \(bu 4
Do not compress the audit log.
.RE
.RE
.PP
Available only in MongoDB Enterprise (http://www.mongodb.com/products/mongodb\-enterprise\-advanced?tck=docs_server)\&.
MongoDB Enterprise and Atlas have different configuration
requirements.
.RE
.PP
\fBmongos \-\-auditDestination\f1
.RS
.PP
Enables \fBauditing\f1 and specifies where
\fBmongos\f1 sends all audit events.
.PP
\fB\-\-auditDestination\f1\f1 can have one of the following values:
.RS
.IP \(bu 2
.RS
.IP \(bu 4
Value
.IP \(bu 4
Description
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBsyslog\f1
.IP \(bu 4
Output the audit events to syslog in JSON format. Not available on
Windows. Audit messages have a syslog severity level of \fBinfo\f1
and a facility level of \fBuser\f1\&.
.IP
The syslog message limit can result in the truncation of
audit messages. The auditing system neither detects the
truncation nor errors upon its occurrence.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBconsole\f1
.IP \(bu 4
Output the audit events to \fBstdout\f1 in JSON format.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBfile\f1
.IP \(bu 4
Output the audit events to the file specified in
\fB\-\-auditPath\f1\f1 in the format specified in
\fB\-\-auditFormat\f1\f1\&.
.RE
.RE
.PP
Available only in MongoDB Enterprise (http://www.mongodb.com/products/mongodb\-enterprise\-advanced?tck=docs_server)
and MongoDB Atlas (https://cloud.mongodb.com/user#/atlas/login)\&.
.RE
.PP
\fBmongos \-\-auditEncryptionKeyUID\f1
.RS
.PP
Specifies the unique identifier of the Key Management
Interoperability Protocol (KMIP) key for \fBaudit log encryption\f1\&.
.PP
You cannot use \fB\-\-auditEncryptionKeyUID\f1\f1 and
\fB\-\-auditLocalKeyFile\f1\f1 together.
.PP
Available only in MongoDB Enterprise (http://www.mongodb.com/products/mongodb\-enterprise\-advanced?tck=docs_server)\&.
MongoDB Enterprise and Atlas have different configuration
requirements.
.RE
.PP
\fBmongos \-\-auditFormat\f1
.RS
.PP
Specifies the format of the output file for \fBauditing\f1 if \fB\-\-auditDestination\f1\f1 is \fBfile\f1\&. The
\fB\-\-auditFormat\f1\f1 option can have one of the following values:
.RS
.IP \(bu 2
.RS
.IP \(bu 4
Value
.IP \(bu 4
Description
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBJSON\f1
.IP \(bu 4
Output the audit events in JSON format to the file specified
in \fB\-\-auditPath\f1\f1\&.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBBSON\f1
.IP \(bu 4
Output the audit events in BSON binary format to the file
specified in \fB\-\-auditPath\f1\f1\&.
.RE
.RE
.PP
Printing audit events to a file in JSON format degrades server
performance more than printing to a file in BSON format.
.PP
Available only in MongoDB Enterprise (http://www.mongodb.com/products/mongodb\-enterprise\-advanced?tck=docs_server)
and MongoDB Atlas (https://cloud.mongodb.com/user#/atlas/login)\&.
.RE
.PP
\fBmongos \-\-auditLocalKeyFile\f1
.RS
.PP
Specifies the path and file name for a local audit key file for
\fBaudit log encryption\f1\&.
.PP
Only use \fB\-\-auditLocalKeyFile\f1\f1 for testing because the key is
not secured. To secure the key, use
\fB\-\-auditEncryptionKeyUID\f1\f1 and an external Key
Management Interoperability Protocol (KMIP) server.
.PP
You cannot use \fB\-\-auditLocalKeyFile\f1\f1 and
\fB\-\-auditEncryptionKeyUID\f1\f1 together.
.PP
Available only in MongoDB Enterprise (http://www.mongodb.com/products/mongodb\-enterprise\-advanced?tck=docs_server)\&.
MongoDB Enterprise and Atlas have different configuration
requirements.
.RE
.PP
\fBmongos \-\-auditPath\f1
.RS
.PP
Specifies the output file for auditing if
\fB\-\-auditDestination\f1\f1 has value of \fBfile\f1\&. The
\fB\-\-auditPath\f1\f1 option can take either a full path name or a
relative path name.
.PP
Available only in MongoDB Enterprise (http://www.mongodb.com/products/mongodb\-enterprise\-advanced?tck=docs_server)
and MongoDB Atlas (https://cloud.mongodb.com/user#/atlas/login)\&.
.RE
.PP
\fBmongos \-\-auditFilter\f1
.RS
.PP
Specifies the filter to limit the \fBtypes of operations\f1 the \fBaudit system\f1 records. The option takes a string representation
of a query document of the form:
.PP
.EX
  { <field1>: <expression1>, ... }
.EE
.PP
The \fB<field>\f1 can be \fBany field in the audit message\f1, including fields returned in the
\fBparam\f1 document. The
\fB<expression>\f1 is a \fBquery condition expression\f1\&.
.PP
To specify an audit filter, enclose the filter document in single
quotes to pass the document as a string.
.PP
To specify the audit filter in a \fBconfiguration file\f1, you must use the YAML format of
the configuration file.
.PP
Available only in MongoDB Enterprise (http://www.mongodb.com/products/mongodb\-enterprise\-advanced?tck=docs_server)
and MongoDB Atlas (https://cloud.mongodb.com/user#/atlas/login)\&.
.RE
.PP
\fBmongos \-\-auditSchema\f1
.RS
.PP
\fIType\f1: string
.PP
\fIDefault\f1: \fBmongo\f1
.PP
Specifies the format used for audit logs. You can specify one of the
following values for \fB\-\-auditSchema\f1:
.RS
.IP \(bu 2
.RS
.IP \(bu 4
Value
.IP \(bu 4
Description
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBmongo\f1
.IP \(bu 4
Logs are written in a format designed by MongoDB.
.IP
For example log messages, see \fBmongo Schema Audit Messages\f1\&.
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBOCSF\f1
.IP \(bu 4
Logs are written in OCSF (Open Cybersecurity Schema
Framework) format. This option provides logs in a standardized
format compatible with log processors.
.IP
For example log messages, see \fBOCSF Schema Audit Messages\f1\&.
.RE
.RE
.RE
.SS PROFILER OPTIONS
.PP
\fBmongos \-\-slowms\f1
.RS
.PP
\fIDefault\f1: 100
.PP
The \fIslow\f1 operation time threshold, in milliseconds. Operations
that run for longer than this threshold are considered \fIslow\f1\&.
.PP
When \fBlogLevel\f1\f1 is set to \fB0\f1, MongoDB records \fIslow\f1
operations to the diagnostic log at a rate determined by
\fBslowOpSampleRate\f1\f1\&.
.PP
At higher \fBlogLevel\f1\f1 settings, all operations appear
in the diagnostic log regardless of their latency.
.PP
For \fBmongos\f1 instances,  affects the diagnostic
log only and not the profiler since profiling is not available on
\fBmongos\f1\&.
.RE
.PP
\fBmongos \-\-slowOpSampleRate\f1
.RS
.PP
\fIDefault\f1: 1.0
.PP
The fraction of \fIslow\f1 operations that should be logged.
\fB\-\-slowOpSampleRate\f1\f1 accepts values between 0 and 1, inclusive.
.PP
For \fBmongos\f1 instances, \fB\-\-slowOpSampleRate\f1\f1 affects the diagnostic log
only and not the profiler since profiling is not available on
\fBmongos\f1\&.
.RE
.SS LDAP AUTHENTICATION AND AUTHORIZATION OPTIONS
.PP
\fBmongos \-\-ldapServers\f1
.RS
.PP
\fIAvailable in MongoDB Enterprise only.\f1
.PP
The LDAP server against which the \fBmongos\f1 authenticates users or
determines what actions a user is authorized to perform on a given
database. If the LDAP server specified has any replicated instances,
you may specify the host and port of each replicated server in a
comma\-delimited list.
.PP
If your LDAP infrastructure partitions the LDAP directory over multiple LDAP
servers, specify \fIone\f1 LDAP server or any of its replicated instances to
\fB\-\-ldapServers\f1\f1\&. MongoDB supports following LDAP referrals as defined in RFC 4511
4.1.10 (https://www.rfc\-editor.org/rfc/rfc4511.txt)\&. Do not use \fB\-\-ldapServers\f1\f1
for listing every LDAP server in your infrastructure.
.PP
This setting can be configured on a running \fBmongos\f1 using
\fBsetParameter\f1\f1\&.
.PP
If unset, \fBmongos\f1 cannot use \fBLDAP authentication or authorization\f1\&.
.RE
.PP
\fBmongos \-\-ldapValidateLDAPServerConfig\f1
.RS
.PP
\fIAvailable in MongoDB Enterprise\f1
.PP
A flag that determines if the \fBmongos\f1 instance checks
the availability of the \fBLDAP server(s)\f1\f1 as part of its startup:
.RS
.IP \(bu 2
If \fBtrue\f1, the \fBmongos\f1 instance performs the
availability check and only continues to start up if the LDAP
server is available.
.IP \(bu 2
If \fBfalse\f1, the \fBmongos\f1 instance skips the
availability check; i.e. the instance starts up even if the LDAP
server is unavailable.
.RE
.RE
.PP
\fBmongos \-\-ldapQueryUser\f1
.RS
.PP
\fIAvailable in MongoDB Enterprise only.\f1
.PP
The identity with which \fBmongos\f1 binds as, when connecting to or
performing queries on an LDAP server.
.PP
Only required if any of the following are true:
.RS
.IP \(bu 2
Using \fBLDAP authorization\f1\&.
.IP \(bu 2
Using an LDAP query for \fBusername transformation\f1\f1\&.
.IP \(bu 2
The LDAP server disallows anonymous binds
.RE
.PP
You must use \fB\-\-ldapQueryUser\f1\f1 with \fB\-\-ldapQueryPassword\f1\f1\&.
.PP
If unset, \fBmongos\f1 doesn\(aqt attempt to bind to the LDAP server.
.PP
This setting can be configured on a running \fBmongos\f1 using
\fBsetParameter\f1\f1\&.
.PP
Windows MongoDB deployments can use \fB\-\-ldapBindWithOSDefaults\f1\f1
instead of \fB\-\-ldapQueryUser\f1\f1 and \fB\-\-ldapQueryPassword\f1\f1\&. You cannot specify
both \fB\-\-ldapQueryUser\f1\f1 and \fB\-\-ldapBindWithOSDefaults\f1\f1 at the same time.
.RE
.PP
\fBmongos \-\-ldapQueryPassword\f1
.RS
.PP
\fIAvailable in MongoDB Enterprise only.\f1
.PP
The password used to bind to an LDAP server when using
\fB\-\-ldapQueryUser\f1\f1\&. You must use \fB\-\-ldapQueryPassword\f1\f1 with
\fB\-\-ldapQueryUser\f1\f1\&.
.PP
If unset, \fBmongos\f1 doesn\(aqt attempt to bind to the LDAP server.
.PP
This setting can be configured on a running \fBmongos\f1 using
\fBsetParameter\f1\f1\&.
.PP
Windows MongoDB deployments can use \fB\-\-ldapBindWithOSDefaults\f1\f1
instead of \fB\-\-ldapQueryPassword\f1\f1 and \fB\-\-ldapQueryPassword\f1\f1\&. You cannot specify
both \fB\-\-ldapQueryPassword\f1\f1 and \fB\-\-ldapBindWithOSDefaults\f1\f1 at the same time.
.RE
.PP
\fBmongos \-\-ldapBindWithOSDefaults\f1
.RS
.PP
\fIDefault\f1: false
.PP
Available in MongoDB Enterprise for the Windows platform only.
.PP
Allows \fBmongos\f1 to authenticate, or bind, using your Windows login
credentials when connecting to the LDAP server.
.PP
Only required if:
.RS
.IP \(bu 2
Using \fBLDAP authorization\f1\&.
.IP \(bu 2
Using an LDAP query for \fBusername transformation\f1\f1\&.
.IP \(bu 2
The LDAP server disallows anonymous binds
.RE
.PP
Use \fB\-\-ldapBindWithOSDefaults\f1\f1 to replace \fB\-\-ldapQueryUser\f1\f1 and
\fB\-\-ldapQueryPassword\f1\f1\&.
.RE
.PP
\fBmongos \-\-ldapBindMethod\f1
.RS
.PP
\fIDefault\f1: simple
.PP
\fIAvailable in MongoDB Enterprise only.\f1
.PP
The method \fBmongos\f1 uses to authenticate to an LDAP server.
Use with \fB\-\-ldapQueryUser\f1\f1 and \fB\-\-ldapQueryPassword\f1\f1 to
connect to the LDAP server.
.PP
\fB\-\-ldapBindMethod\f1\f1 supports the following values:
.RS
.IP \(bu 2
\fBsimple\f1 \- \fBmongos\f1 uses simple authentication.
.IP \(bu 2
\fBsasl\f1 \- \fBmongos\f1 uses SASL protocol for authentication
.RE
.PP
If you specify \fBsasl\f1, you can configure the available SASL mechanisms
using \fB\-\-ldapBindSaslMechanisms\f1\f1\&. \fBmongos\f1 defaults to
using \fBDIGEST\-MD5\f1 mechanism.
.RE
.PP
\fBmongos \-\-ldapBindSaslMechanisms\f1
.RS
.PP
\fIDefault\f1: DIGEST\-MD5
.PP
\fIAvailable in MongoDB Enterprise only.\f1
.PP
A comma\-separated list of SASL mechanisms \fBmongos\f1 can
use when authenticating to the LDAP server. The \fBmongos\f1 and the
LDAP server must agree on at least one mechanism. The \fBmongos\f1
dynamically loads any SASL mechanism libraries installed on the host
machine at runtime.
.PP
Install and configure the appropriate libraries for the selected
SASL mechanism(s) on both the \fBmongos\f1 host and the remote
LDAP server host. Your operating system may include certain SASL
libraries by default. Defer to the documentation associated with each
SASL mechanism for guidance on installation and configuration.
.PP
If using the \fBGSSAPI\f1 SASL mechanism for use with
\fBKerberos Authentication\f1, verify the following for the
\fBmongos\f1 host machine:
.PP
\fBLinux\f1\f1
.RS
.RS
.IP \(bu 2
The \fBKRB5_CLIENT_KTNAME\f1 environment
variable resolves to the name of the client \fBLinux Keytab Files\f1
for the host machine. For more on Kerberos environment
variables, please defer to the
Kerberos documentation (https://web.mit.edu/kerberos/krb5\-1.13/doc/admin/env_variables.html)\&.
.IP \(bu 2
The client keytab includes a
\fBUser Principal\f1 for the \fBmongos\f1 to use when
connecting to the LDAP server and execute LDAP queries.
.RE
.RE
.PP
\fBWindows\f1\f1
.RS
.PP
If connecting to an Active Directory server, the Windows
Kerberos configuration automatically generates a
Ticket\-Granting\-Ticket (https://msdn.microsoft.com/en\-us/library/windows/desktop/aa380510(v=vs.85).aspx)
when the user logs onto the system. Set \fB\-\-ldapBindWithOSDefaults\f1\f1 to
\fBtrue\f1 to allow \fBmongos\f1 to use the generated credentials when
connecting to the Active Directory server and execute queries.
.RE
.PP
Set \fB\-\-ldapBindMethod\f1\f1 to \fBsasl\f1 to use this option.
.PP
For a complete list of SASL mechanisms see the
IANA listing (http://www.iana.org/assignments/sasl\-mechanisms/sasl\-mechanisms.xhtml)\&.
Defer to the documentation for your LDAP or Active Directory
service for identifying the SASL mechanisms compatible with the
service.
.PP
MongoDB is not a source of SASL mechanism libraries, nor
is the MongoDB documentation a definitive source for
installing or configuring any given SASL mechanism. For
documentation and support, defer to the SASL mechanism
library vendor or owner.
.PP
For more information on SASL, defer to the following resources:
.RS
.IP \(bu 2
For Linux, please see the Cyrus SASL documentation (https://www.cyrusimap.org/sasl/)\&.
.IP \(bu 2
For Windows, please see the Windows SASL documentation (https://msdn.microsoft.com/en\-us/library/cc223500.aspx)\&.
.RE
.RE
.PP
\fBmongos \-\-ldapTransportSecurity\f1
.RS
.PP
\fIDefault\f1: tls
.PP
\fIAvailable in MongoDB Enterprise only.\f1
.PP
By default, \fBmongos\f1 creates a TLS/SSL secured connection to the LDAP
server.
.PP
For Linux deployments, you must configure the appropriate TLS Options in
\fB/etc/openldap/ldap.conf\f1 file. Your operating system\(aqs package manager
creates this file as part of the MongoDB Enterprise installation, via the
\fBlibldap\f1 dependency. See the documentation for \fBTLS Options\f1 in the
ldap.conf OpenLDAP documentation (http://www.openldap.org/software/man.cgi?query=ldap.conf&manpath=OpenLDAP+2.4\-Release)
for more complete instructions.
.PP
For Windows deployment, you must add the LDAP server CA certificates to the
Windows certificate management tool. The exact name and functionality of the
tool may vary depending on operating system version. Please see the
documentation for your version of Windows for more information on
certificate management.
.PP
Set \fB\-\-ldapTransportSecurity\f1\f1 to \fBnone\f1 to disable TLS/SSL between \fBmongos\f1 and the LDAP
server.
.PP
Setting \fB\-\-ldapTransportSecurity\f1\f1 to \fBnone\f1 transmits plaintext information and possibly
credentials between \fBmongos\f1 and the LDAP server.
.RE
.PP
\fBmongos \-\-ldapTimeoutMS\f1
.RS
.PP
\fIDefault\f1: 10000
.PP
\fIAvailable in MongoDB Enterprise only.\f1
.PP
The amount of time in milliseconds \fBmongos\f1 should wait for an LDAP server
to respond to a request.
.PP
Increasing the value of \fB\-\-ldapTimeoutMS\f1\f1 may prevent connection failure between the
MongoDB server and the LDAP server, if the source of the failure is a
connection timeout. Decreasing the value of \fB\-\-ldapTimeoutMS\f1\f1 reduces the time
MongoDB waits for a response from the LDAP server.
.PP
This setting can be configured on a running \fBmongos\f1 using
\fBsetParameter\f1\f1\&.
.RE
.PP
\fBmongos \-\-ldapRetryCount\f1
.RS
.PP
\fIDefault\f1: 0
.PP
\fIAvailable in MongoDB Enterprise only.\f1
.PP
Number of operation retries by the server LDAP manager after a
network error.
.RE
.PP
\fBmongos \-\-ldapUserToDNMapping\f1
.RS
.PP
\fIAvailable in MongoDB Enterprise only.\f1
.PP
Maps the username provided to \fBmongos\f1 for authentication to a LDAP
Distinguished Name (DN). You may need to use \fB\-\-ldapUserToDNMapping\f1\f1 to transform a
username into an LDAP DN in the following scenarios:
.RS
.IP \(bu 2
Performing LDAP authentication with simple LDAP binding, where users
authenticate to MongoDB with usernames that are not full LDAP DNs.
.IP \(bu 2
Using an \fBLDAP authorization query template\f1\f1 that requires a DN.
.IP \(bu 2
Transforming the usernames of clients authenticating to Mongo DB
using different authentication mechanisms, such as x.509 or
kerberos, to a full LDAP DN for authorization.
.RE
.PP
\fB\-\-ldapUserToDNMapping\f1\f1 expects a quote\-enclosed JSON\-string representing an ordered array
of documents. Each document contains a regular expression \fBmatch\f1 and
either a \fBsubstitution\f1 or \fBldapQuery\f1 template used for transforming the
incoming username.
.PP
Each document in the array has the following form:
.PP
.EX
  {
    match: "<regex>"
    substitution: "<LDAP DN>" | ldapQuery: "<LDAP Query>"
  }
.EE
.RS
.IP \(bu 2
.RS
.IP \(bu 4
Field
.IP \(bu 4
Description
.IP \(bu 4
Example
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBmatch\f1
.IP \(bu 4
An ECMAScript\-formatted regular expression (regex) to match against a
provided username. Each parenthesis\-enclosed section represents a
regex capture group used by \fBsubstitution\f1 or \fBldapQuery\f1\&.
.IP \(bu 4
\fB"(.+)ENGINEERING"\f1
\fB"(.+)DBA"\f1
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBsubstitution\f1
.IP \(bu 4
An LDAP distinguished name (DN) formatting template that converts the
authentication name matched by the \fBmatch\f1 regex into a LDAP DN.
Each curly bracket\-enclosed numeric value is replaced by the
corresponding regex capture group (http://www.regular\-expressions.info/refcapture.html) extracted
from the authentication username via the \fBmatch\f1 regex.
.IP
The result of the substitution must be an RFC4514 (https://www.ietf.org/rfc/rfc4514.txt) escaped string.
.IP \(bu 4
\fB"cn={0},ou=engineering,
dc=example,dc=com"\f1
.RE
.IP \(bu 2
.RS
.IP \(bu 4
\fBldapQuery\f1
.IP \(bu 4
A LDAP query formatting template that inserts the authentication
name matched by the \fBmatch\f1 regex into an LDAP query URI encoded
respecting RFC4515 and RFC4516. Each curly bracket\-enclosed numeric
value is replaced by the corresponding regex capture group (http://www.regular\-expressions.info/refcapture.html) extracted
from the authentication username via the \fBmatch\f1 expression.
\fBmongos\f1 executes the query against the LDAP server to retrieve
the LDAP DN for the authenticated user. \fBmongos\f1 requires
exactly one returned result for the transformation to be
successful, or \fBmongos\f1 skips this transformation.
.IP \(bu 4
\fB"ou=engineering,dc=example,
dc=com??one?(user={0})"\f1
.RE
.RE
.PP
An explanation of  RFC4514 (https://www.ietf.org/rfc/rfc4514.txt),
RFC4515 (https://tools.ietf.org/html/rfc4515),
RFC4516 (https://tools.ietf.org/html/rfc4516), or LDAP queries is out
of scope for the MongoDB Documentation. Please review the RFC directly or
use your preferred LDAP resource.
.PP
For each document in the array, you must use either \fBsubstitution\f1 or
\fBldapQuery\f1\&. You \fIcannot\f1 specify both in the same document.
.PP
When performing authentication or authorization, \fBmongos\f1 steps through
each document in the array in the given order, checking the authentication
username against the \fBmatch\f1 filter.  If a match is found,
\fBmongos\f1 applies the transformation and uses the output for
authenticating the user. \fBmongos\f1 does not check the remaining documents
in the array.
.PP
If the given document does not match the provided authentication
name, \fBmongos\f1 continues through the list of documents
to find additional matches. If no matches are found in any document,
or the transformation the document describes fails,
\fBmongos\f1 returns an error.
.PP
\fBmongos\f1 also returns an error if one of the transformations cannot be
evaluated due to networking or authentication failures to the LDAP server.
\fBmongos\f1 rejects the connection request and does not check the remaining
documents in the array.
.PP
Starting in MongoDB 5.0, \fB\-\-ldapUserToDNMapping\f1\f1
accepts an empty string \fB""\f1 or empty array \fB[ ]\f1 in place of a
mapping documnent. If providing an empty string or empty array to
\fB\-\-ldapUserToDNMapping\f1\f1, MongoDB maps the
authenticated username as the LDAP DN. Previously, providing an
empty mapping document would cause mapping to fail.
.PP
The following shows two transformation documents. The first
document matches against any string ending in \fB@ENGINEERING\f1, placing
anything preceeding the suffix into a regex capture group. The
second document matches against any string ending in \fB@DBA\f1, placing
anything preceeding the suffix into a regex capture group.
.PP
.EX
  "[
     {
        match: "(.+)@ENGINEERING.EXAMPLE.COM",
        substitution: "cn={0},ou=engineering,dc=example,dc=com"
     },
     {
        match: "(.+)@DBA.EXAMPLE.COM",
        ldapQuery: "ou=dba,dc=example,dc=com??one?(user={0})"
  
     }
  
  ]"
.EE
.PP
A user with username \fBalice@ENGINEERING.EXAMPLE.COM\f1 matches the first
document. The regex capture group \fB{0}\f1 corresponds to the string
\fBalice\f1\&. The resulting output is the DN
\fB"cn=alice,ou=engineering,dc=example,dc=com"\f1\&.
.PP
A user with username \fBbob@DBA.EXAMPLE.COM\f1 matches the second document.
The regex capture group \fB{0}\f1 corresponds to the string \fBbob\f1\&.  The
resulting output is the LDAP query
\fB"ou=dba,dc=example,dc=com??one?(user=bob)"\f1\&. \fBmongos\f1 executes this
query against the LDAP server, returning the result
\fB"cn=bob,ou=dba,dc=example,dc=com"\f1\&.
.PP
If \fB\-\-ldapUserToDNMapping\f1\f1 is unset, \fBmongos\f1 applies no transformations to the username
when attempting to authenticate or authorize a user against the LDAP server.
.PP
This setting can be configured on a running \fBmongos\f1 using the
\fBsetParameter\f1\f1 database command.
.RE
.SS ADDITIONAL OPTIONS
.PP
\fBmongos \-\-ipv6\f1
.RS
.PP
Enables IPv6 support. \fBmongos\f1 disables IPv6 support by default.
.PP
Setting \fB\-\-ipv6\f1\f1 does \fInot\f1 direct the \fBmongos\f1 to listen on any
local IPv6 addresses or interfaces. To configure the \fBmongos\f1 to
listen on an IPv6 interface, you must either:
.RS
.IP \(bu 2
Configure \fB\-\-bind_ip\f1\f1 with one or more IPv6 addresses or
hostnames that resolve to IPv6 addresses, \fBor\f1
.IP \(bu 2
Set \fB\-\-bind_ip_all\f1\f1 to \fBtrue\f1\&.
.RE
.RE