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System Configuration

System settings in Infix are provided by the ietf-system YANG model, augmented with Linux specific extensions in infix-system, like Message of the Day (login message) and user login shell. More on this later on in this document.

For the sake of brevity, the hostname in the following examples has been shortened to host. The default hostname is composed from a product specific string followed by the last three octets of the system base MAC address, e.g., switch-12-34-56. An example of how to change the hostname is included below.

Note: when issuing leave to activate your changes, remember to also save your settings, copy running-config startup-config. See the CLI Introduction for a background.

Changing Password

User management, including passwords, SSH keys, remote authentication is available in the system authentication configuration context.

admin@host:/config/> edit system authentication user admin
admin@host:/config/system/authentication/user/admin/> change password
New password: 
Retype password: 
admin@host:/config/system/authentication/user/admin/> leave

The change password command starts an interactive dialogue that asks for the new password, with a confirmation, and then salts and encrypts the password with sha512crypt.

It is also possible to use the set password ... command. This allows setting an already hashed password. To manually hash a password, use the do password encrypt command. This launches the admin-exec command to hash, and optionally salt, your password. This encrypted string can then be used with set password ....

Tip: if you are having trouble thinking of a password, Infix has a password generate command in admin-exec context which generates random passwords using the UNIX command pwgen. Use the do prefix when inside any configuration context to access admin-exec commands.

SSH Authorized Key

Logging in remotely with SSH is possible by adding a public key to a user. Here we add the authorized key to the admin user, multiple keys are supported.

With SSH keys in place it is possible to disable password login, just remember to verify SSH login and network connectivity before doing so.

admin@host:/config/> edit system authentication user admin 
admin@host:/config/system/authentication/user/admin/> edit authorized-key example@host
admin@host:/config/system/authentication/user/admin/authorized-key/example@host/> set algorithm ssh-rsa
admin@host:/config/system/authentication/user/admin/authorized-key/example@host/> set key-data 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
admin@host:/config/system/authentication/user/admin/authorized-key/example@host/> show
algorithm ssh-rsa;
key-data AAAAB3NzaC1yc2EAAAADAQABAAABgQC8iBL42yeMBioFay7lty1C4ZDTHcHyo739gc91rTTH8SKvAE4g8Rr97KOz/8PFtOObBrE9G21K7d6UBuPqmd0RUF2CkXXN/eN2PBSHJ50YprRFt/z/304bsBYkDdflKlPDjuSmZ/+OMp4pTsq0R0eNFlX9wcwxEzooIb7VPEdvWE7AYoBRUdf41u3KBHuvjGd1M6QYJtbFLQMMTiVe5IUfyVSZ1RCxEyAB9fR9CBhtVheTVsY3iG0fZc9eCEo89ErDgtGUTJK4Hxt5yCNwI88YaVmkE85cNtw8YwubWQL3/tGZHfbbQ0fynfB4kWNloyRHFr7E1kDxuX5+pbv26EqRdcOVGucNn7hnGU6C1+ejLWdBD7vgsoilFrEaBWF41elJEPKDzpszEijQ9gTrrWeYOQ+x++lvmOdssDu4KvGmj2K/MQTL2jJYrMJ7GDzsUu3XikChRL7zNfS2jYYQLzovboUCgqfPUsVba9hqeX3U67GsJo+hy5MG9RSry4+ucHs=;
admin@host:/config/system/authentication/user/admin/authorized-key/example@host/> leave

Note: the ssh-keygen program already base64 encodes the public key data, so there is no need to use the text-editor command, set does the job.

Multiple Users

The system supports multiple users and multiple user levels, or groups, that a user can be a member of. Access control is entirely handled by the NETCONF "NACM" YANG model, which provides granular access to configuration, data, and RPC commands over NETCONF.

By default the system ships with a single group, admin, which the default user admin is a member of. The broad permissions granted by the admin group is what gives its users full system administrator privileges. There are no restrictions on the number of users with administrator privileges, nor is the admin user reserved or protected in any way -- it is completely possible to remove the default admin user from the configuration. However, it is recommended to keep at least one user with administrator privileges in the system, otherwise the only way to regain full access is to perform a factory reset.

Adding a User

Similar to how to change password, adding a new user is done using the same set of commands:

admin@host:/config/> edit system authentication user jacky
admin@host:/config/system/authentication/user/jacky/> change password
New password:
Retype password:
admin@host:/config/system/authentication/user/jacky/> leave

An authorized SSH key is added the same way as presented previously.

Adding a User to the Admin Group

The following commands add user jacky to the admin group.

admin@host:/config/> edit nacm group admin
admin@host:/config/nacm/group/admin/> set user-name jacky
admin@host:/config/nacm/group/admin/> leave

Security Aspects

The NACM user levels apply primarily to NETCONF, with exception of the admin group which is granted full system administrator privileges to the underlying UNIX system with the following ACL rules:

   ...
   "module-name": "*",
   "access-operations": "*",
   "action": "permit",
   ...

A user in the admin group is allowed to also use a POSIX login shell and use the sudo command to perform system administrative commands. This makes it possible to use all the underlying UNIX tooling, which to many can be very useful, in particular when debugging a system, but please remember to use with care -- the system is not built to require managing from the shell. The tools available in the CLI and automated services, started from the system's configuration, are the recommended way of using the system, in addition to NETCONF tooling.

Changing Hostname

Notice how the hostname in the prompt does not change until the change is committed by issuing the leave command.

admin@host:/config/> edit system
admin@host:/config/system/> set hostname example
admin@host:/config/system/> leave
admin@example:/>

The hostname is advertised over mDNS-SD in the .local domain. If another device already has claimed the example.local CNAME, in our case, mDNS will advertise a "uniqified" variant, usually suffixing with an index, e.g., example-1.local. Use an mDNS browser to scan for available devices on your LAN.

Note: critical services like syslog, mDNS, LLDP, and similar that advertise the hostname, are restarted when the hostname is changed.

Changing Login Banner

The motd-banner setting is an Infix augment and an example of a binary type setting that can be changed interactively with the built-in text-editor command.

Tip: see the next section for how to change the editor used to something you may be more familiar with.

admin@host:/config/> edit system
admin@host:/config/system/> text-editor motd-banner
admin@host:/config/system/> leave
admin@host:/>

Log out and log back in again to inspect the changes.

Changing the Editor

The system has three different built-in editors that can be used as the text-editor command:

  • emacs (Micro Emacs)
  • nano (GNU Nano)
  • vi (Visual Editor)

To change the editor to GNU Nano:

admin@host:/> configure
admin@host:/config/> edit system
admin@host:/config/system/> set text-editor nano
admin@host:/config/system/> leave
admin@host:/>

Note: as usual, configuration changes only take effect after issuing the leave command. I.e., you must change the editor first, and then re-enter configure context to use your editor of choice.