Web MTR

Overview

A simple web based traceroute:

• A Python application runs the CLI command mtr and returns the results in JSON format.
• An ICMP/v6 traceroute is performed.
• Running in a NAT64 (IPv6-only) environment is supported if you don't have a dual stack environment!
• The JSON output from mtr is parsed and displayed by a web UI (you can call the API directly to get JSON output).
• UV is used to manage Python dependencies, virtual environments, and to run tests.
• Gunicorn is used to run the web application and control the number of worker processes.
• All application settings are defined in the .env file.
• The application runs inside Docker (the capability NET_RAW is required for mtr to have ICMP privileges).

An example from a NAT64 (IPv6-only!) host.

Usage

# Start the container
docker compose up -d

# Logs are sent to a file
tail -f logs/access.log

GET JSON output by calling the API directly:

curl -s http://localhost:8371/traceroute?target=8.8.8.8 | jq

Open a browser to http://localhost:8371 to use the UI.

Bindings

If you want to bind to a specific IPv6 address, set the LISTEN_ADDR env var using square bracket syntax: LISTEN_ADDR=[fe80::1122:3344:5566:7788]

NAT64

If running on an IPv6 only host which uses NAT64 to provide IPv4 connectivity, ensure the NAT64 env var contains the prefix of the NAT64 network, e.g. NAT64=64:ff9b::/96. Leave this var defined but empty if the host has native IPv4 connectivity.

With this env var set:

• When an IPv4 address is entered as the target, it will be converted to a NAT64 address and the traceroute will be performed using that address.
• When a traceroute is run to a NAT64 prefix (due to an IPv4 literal target or DNS64) the IPv4 addresses of each hop in the results are extracted from the mtr output and displayed as IPv4 addresses, along with their reverse DNS lookup result, and the ASN of the IPv4 address; rather than the NAT64 addresses (which have no reverse DNS or ASN information).

Tests

uv run pytest src/tests.py -q