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DNSViz

Table of Contents

Description

DNSViz is a tool suite for analysis and visualization of Domain Name System (DNS) behavior, including its security extensions (DNSSEC). This tool suite powers the Web-based analysis available at https://dnsviz.net/

Installation

DNSViz packages are available in repositories for popular operating systems, such as Debian, Ubuntu, and FreeBSD. DNSViz can also be installed on Mac OS X via Homebrew or MacPorts.

The remainer of this section covers other methods of installation, including a list of dependencies, installation to a virtual environment, and installation on Fedora, RHEL 8, CentOS 8, and RHEL 7.

Instructions for running in a Docker container are also available later in this document.

Dependencies

Note that earlier versions of the software listed above might also work with DNSViz, but with some caveats. For example, M2Crypto 0.28.0 and later will work, but versions of M2Crypto earlier than 0.37.0 lack support for DNSSEC algorithms 15 (Ed25519) and 16 (Ed448). Also, while DNSViz itself still works with python 2.7, some versions of its software dependencies have moved on: pygraphviz 1.6 and dnspython 2.0.0 dropped support for python 2.7.

Optional Software

  • OpenSSL GOST Engine - https://github.com/gost-engine/engine

    With OpenSSL version 1.1.0 and later, the OpenSSL GOST Engine is necessary to validate DNSSEC signatures with algorithm 12 (GOST R 34.10-2001) and create digests of type 3 (GOST R 34.11-94).

  • ISC BIND - https://www.isc.org/bind/

    When using DNSViz for pre-deployment testing by specifying zone files and/or alternate delegation information on the command line (i.e., with -N, -x, or -D), named(8) is invoked to serve one or more zones. ISC BIND is only needed in this case, and named(8) does not need to be running (i.e., as a server).

    Note that default AppArmor policies for Debian are known to cause issues when invoking named(8) from DNSViz for pre-deployment testing. Two solutions to this problem are to either: 1) create a local policy for AppArmor that allows named(8) to run with fewer restrictions; or 2) disable AppArmor completely.

Installation in a Virtual Environment

To install DNSViz to a virtual environment, first create and activate a virtual environment, and install the dependencies:

$ virtualenv ~/myenv
$ source ~/myenv/bin/activate
(myenv) $ pip install -r requirements.txt

(Note that this installs the dependencies that are python packages, but some of these packages have non-python dependecies, such as Graphviz (required for pygraphviz) that are not installed automatically.)

Next download and install DNSViz from the Python Package Index (PyPI):

(myenv) $ pip install dnsviz

or locally, from a downloaded or cloned copy of DNSViz:

(myenv) $ pip install .

Fedora / RHEL 8 / CentOS 8 RPM Build and Install

RHEL 8 only: Enable CodeReady Linux Builder by following the instructions here.

CentOS 8 only: Enable PowerTools and EPEL with the following two commands:

$ sudo dnf config-manager --set-enabled powertools
$ sudo dnf install epel-release

The remaining instructions are for Fedora, RHEL 8, and CentOS 8.

Install the tools for building an RPM, and set up the rpmbuild tree.

$ sudo dnf install rpm-build rpmdevtools python3-devel
$ rpmdev-setuptree

From within the DNSViz source directory, create a source distribution tarball and copy it and the DNSViz spec file to the appropriate rpmbuild subdirectories.

$ python3 setup.py sdist
$ cp dist/dnsviz-*.tar.gz ~/rpmbuild/SOURCES/
$ cp contrib/dnsviz.spec ~/rpmbuild/SPECS/

Install dnspython, pygraphviz, and M2Crypto.

$ sudo dnf install python3-dns python3-pygraphviz python3-m2crypto

(Note that as of Fedora 33 / RHEL 8 / CentOS 8, the latest version of M2Crypto is 0.35.2. If you would like support for DNSSEC algorithms 15 (Ed25519) and 16 (Ed448), you will need to install M2Crypto using pip3. For example, see installation to a virtual environment.)

Build and install the DNSViz RPM.

$ rpmbuild -ba rpmbuild/SPECS/dnsviz.spec
$ sudo rpm -iv rpmbuild/RPMS/noarch/dnsviz-*-1.*.noarch.rpm

RHEL 7 RPM Build and Install

Install pygraphviz, M2Crypto, and dnspython, after installing their build dependencies.

$ sudo yum install python3 gcc python3-devel graphviz-devel openssl-devel swig
$ pip3 install --user pbr m2crypto pygraphviz dnspython

Install rpm-build tools, then build and install the DNSViz RPM.

$ sudo yum install rpm-build
$ python3 setup.py bdist_rpm --install-script contrib/rpm-install.sh --distribution-name el7
$ sudo rpm -iv dist/dnsviz-*-1.noarch.rpm

Note that a custom install script is used to properly install the DNSViz man pages.

Usage

DNSViz is invoked using the dnsviz command-line utility. dnsviz itself uses several subcommands: probe, grok, graph, print, and query. See the man pages associated with each subcommand, in the form of "dnsviz- (1)" (e.g., "man dnsviz-probe") for more detailed documentation and usage.

dnsviz probe

dnsviz probe takes one or more domain names as input and performs a series of queries to either recursive (default) or authoritative DNS servers, the results of which are serialized into JSON format.

Examples

Analyze the domain name example.com using your configured DNS resolvers (i.e., in /etc/resolv.conf) and store the queries and responses in the file named "example.com.json":

$ dnsviz probe example.com > example.com.json

Same thing:

$ dnsviz probe -o example.com.json example.com

Analyze the domain name example.com by querying its authoritative servers directly:

$ dnsviz probe -A -o example.com.json example.com

Analyze the domain name example.com by querying explicitly-defined authoritative servers, rather than learning the servers through referrals from the IANA root servers:

$ dnsviz probe -A \
  -x example.com:a.iana-servers.org=199.43.132.53,a.iana-servers.org=[2001:500:8c::53] \
  -x example.com:b.iana-servers.org=199.43.133.53,b.iana-servers.org=[2001:500:8d::53] \
  -o example.com.json example.com

Same, but have dnsviz probe resolve the names:

$ dnsviz probe -A \
  -x example.com:a.iana-servers.org,b.iana-servers.org \
  -o example.com.json example.com

Analyze the domain name example.com and its entire ancestry by querying authoritative servers and following delegations, starting at the root:

$ dnsviz probe -A -a . -o example.com.json example.com

Analyze multiple names in parallel (four threads) using explicit recursive resolvers (replace 192.0.1.2 and 2001:db8::1 with legitimate resolver addresses):

$ dnsviz probe -s 192.0.2.1,[2001:db8::1] -t 4 -o multiple.json \
  example.com sandia.gov verisignlabs.com dnsviz.net

dnsviz grok

dnsviz grok takes serialized query results in JSON format (i.e., output from dnsviz probe) as input and assesses specified domain names based on their corresponding content in the input. The output is also serialized into JSON format.

Examples

Process the query/response output produced by dnsviz probe, and store the serialized results in a file named "example.com-chk.json":

$ dnsviz grok < example.com.json > example.com-chk.json

Same thing:

$ dnsviz grok -r example.com.json -o example.com-chk.json example.com

Show only info-level information: descriptions, statuses, warnings, and errors:

$ dnsviz grok -l info -r example.com.json -o example.com-chk.json

Show descriptions only if there are related warnings or errors:

$ dnsviz grok -l warning -r example.com.json -o example.com-chk.json

Show descriptions only if there are related errors:

$ dnsviz grok -l error -r example.com.json -o example.com-chk.json

Use root key as DNSSEC trust anchor, to additionally indicate authentication status of responses:

$ dig +noall +answer . dnskey | awk '$5 % 2 { print $0 }' > tk.txt
$ dnsviz grok -l info -t tk.txt -r example.com.json -o example.com-chk.json

Pipe dnsviz probe output directly to dnsviz grok:

$ dnsviz probe example.com | \
      dnsviz grok -l info -o example.com-chk.json

Same thing, but save the raw output (for re-use) along the way:

$ dnsviz probe example.com | tee example.com.json | \
      dnsviz grok -l info -o example.com-chk.json

Assess multiple names at once with error level:

$ dnsviz grok -l error -r multiple.json -o example.com-chk.json

dnsviz graph

dnsviz graph takes serialized query results in JSON format (i.e., output from dnsviz probe) as input and assesses specified domain names based on their corresponding content in the input. The output is an image file, a dot (directed graph) file, or an HTML file, depending on the options passed.

Examples

Process the query/response output produced by dnsviz probe, and produce a graph visually representing the results in a png file named "example.com.png".

$ dnsviz graph -Tpng < example.com.json > example.com.png

Same thing:

$ dnsviz graph -Tpng -o example.com.png example.com < example.com.json

Same thing, but produce interactive HTML format: interactive HTML output in a file named "example.com.html":

$ dnsviz graph -Thtml < example.com.json > example.com.html

Same thing (filename is derived from domain name and output format):

$ dnsviz graph -Thtml -O -r example.com.json

Use alternate DNSSEC trust anchor:

$ dig +noall +answer example.com dnskey | awk '$5 % 2 { print $0 }' > tk.txt
$ dnsviz graph -Thtml -O -r example.com.json -t tk.txt

Pipe dnsviz probe output directly to dnsviz graph:

$ dnsviz probe example.com | \
      dnsviz graph -Thtml -O

Same thing, but save the raw output (for re-use) along the way:

$ dnsviz probe example.com | tee example.com.json | \
      dnsviz graph -Thtml -O

Process analysis of multiple domain names, creating an image for each name processed:

$ dnsviz graph -Thtml -O -r multiple.json

Process analysis of multiple domain names, creating a single image for all names.

$ dnsviz graph -Thtml -r multiple.json > multiple.html

dnsviz print

dnsviz print takes serialized query results in JSON format (i.e., output from dnsviz probe) as input and assesses specified domain names based on their corresponding content in the input. The output is textual output suitable for file or terminal display.

Examples

Process the query/response output produced by dnsviz probe, and output the results to the terminal:

$ dnsviz print < example.com.json

Use alternate DNSSEC trust anchor:

$ dig +noall +answer example.com dnskey | awk '$5 % 2 { print $0 }' > tk.txt
$ dnsviz print -r example.com.json -t tk.txt

Pipe dnsviz probe output directly to dnsviz print:

$ dnsviz probe example.com | \
      dnsviz print

Same thing, but save the raw output (for re-use) along the way:

$ dnsviz probe example.com | tee example.com.json | \
      dnsviz print

dnsviz query

dnsviz query is a wrapper that couples the functionality of dnsviz probe and dnsviz print into a tool with minimal dig-like usage, used to make analysis queries and return the textual output to terminal or file output in one go.

Examples

Analyze the domain name example.com using the first of your configured DNS resolvers (i.e., in /etc/resolv.conf):

$ dnsviz query example.com

Same, but specify an alternate trust anchor:

$ dnsviz query +trusted-key=tk.txt example.com

Analyze example.com through the recursive resolver at 192.0.2.1:

$ dnsviz query @192.0.2.1 +trusted-key=tk.txt example.com

Pre-Deployment DNS Testing

The examples in this section demonstrate usage of DNSViz for pre-deployment testing.

Pre-Delegation Testing

The following examples involve issuing diagnostic queries for a zone before it is ever delegated.

Issue queries against a zone file on the local system (example.com.zone). named(8) is invoked to serve the file locally:

$ dnsviz probe -A -x example.com+:example.com.zone example.com

(Note the use of "+", which designates that the parent servers should not be queried for DS records.)

Issue queries to a server that is serving the zone:

$ dnsviz probe -A -x example.com+:192.0.2.1 example.com

(Note that this server doesn't need to be a server in the NS RRset for example.com.)

Issue queries to the servers in the authoritative NS RRset, specified by name and/or address:

$ dnsviz probe -A \
      -x example.com+:ns1.example.com=192.0.2.1 \
      -x example.com+:ns2.example.com=192.0.2.1,ns2.example.com=[2001:db8::1] \
      example.com

Specify the names and addresses corresponding to the future delegation NS records and (as appropriate) A/AAAA glue records in the parent zone (com):

$ dnsviz probe -A \
      -N example.com:ns1.example.com=192.0.2.1 \
      -N example.com:ns2.example.com=192.0.2.1,ns2.example.com=[2001:db8::1] \
      example.com

Also supply future DS records:

$ dnsviz probe -A \
      -N example.com:ns1.example.com=192.0.2.1 \
      -N example.com:ns2.example.com=192.0.2.1,ns2.example.com=[2001:db8::1] \
      -D example.com:dsset-example.com. \
      example.com

Pre-Deployment Testing of Authoritative Zone Changes

The following examples involve issuing diagnostic queries for a delegated zone before changes are deployed.

Issue diagnostic queries for a new zone file that has been created but not yet been deployed (i.e., with changes to DNSKEY or other records):

$ dnsviz probe -A -x example.com:example.com.zone example.com

(Note the absence of "+", which designates that the parent servers will be queried for DS records.)

Issue queries to a server that is serving the new version of the zone:

$ dnsviz probe -A -x example.com:192.0.2.1 example.com

(Note that this server doesn't need to be a server in the NS RRset for example.com.)

Pre-Deployment Testing of Delegation Changes

The following examples involve issuing diagnostic queries for a delegated zone before changes are deployed to the delegation, glue, or DS records for that zone.

Specify the names and addresses corresponding to the new delegation NS records and (as appropriate) A/AAAA glue records in the parent zone (com):

$ dnsviz probe -A \
      -N example.com:ns1.example.com=192.0.2.1 \
      -N example.com:ns2.example.com=192.0.2.1,ns2.example.com=[2001:db8::1] \
      example.com

Also supply the replacement DS records:

$ dnsviz probe -A \
      -N example.com:ns1.example.com=192.0.2.1 \
      -N example.com:ns2.example.com=192.0.2.1,ns2.example.com=[2001:db8::1] \
      -D example.com:dsset-example.com. \
      example.com

Docker Container

A ready-to-use docker container is available for use.

docker pull dnsviz/dnsviz

This section only covers Docker-related examples, for more information see the Usage section.

Simple Usage

$ docker run dnsviz/dnsviz help
$ docker run dnsviz/dnsviz query example.com

Working with Files

It might be useful to mount a local working directory into the container, especially when combining multiple commands or working with zone files.

$ docker run -v "$PWD:/data:rw" dnsviz/dnsviz probe dnsviz.net > probe.json
$ docker run -v "$PWD:/data:rw" dnsviz/dnsviz graph -r probe.json -T png -O

Using a Host Network

When running authoritative queries, a host network is recommended.

$ docker run --network host dnsviz/dnsviz probe -4 -A example.com > example.json

Otherwise, you're likely to encounter the following error: dnsviz.query.SourceAddressBindError: Unable to bind to local address (EADDRNOTAVAIL)

Interactive Mode

When performing complex analyses, where you need to combine multiple DNSViz commands, use bash redirection, etc., it might be useful to run the container interactively:

$ docker run --network host -v "$PWD:/data:rw" --entrypoint /bin/sh -ti dnsviz/dnsviz
/data # dnsviz --help