mtrx

A custom MTR / traceroute client that colour-highlights bogon and special-use IP space and resolves each hop's origin AS number to its organisation name — plus reverse DNS, per-hop loss/latency statistics, and a live terminal UI.

Hop  Host / AS                                Loss%  Snt   Last   Avg  Best  Wrst  StDev  Recent
 1   10.10.40.1 [private]                      0.0%    8    0.6   0.6   0.6   0.7    0.1   ▄▁▂▄█
 2   vl17.core02-toh-fi.as206125.net  AS206125 TIMNET, FI [FI]   0.0% …
 …
13   one.one.one.one  AS13335 CLOUDFLARENET - Cloudflare, Inc. [AU]  0.0% …

Features

• Bogon / special-use highlighting — longest-prefix classification of RFC 1918 private, RFC 6598 CGNAT, loopback, link-local, IPv6 ULA, documentation, benchmarking, multicast and reserved/future ranges (IPv4 & IPv6), colour-coded by category.
• ASN → organisation resolution via Team Cymru's DNS whois service (no API key), with in-memory caching. Shows AS<n> <org> [<country>].
• Reverse DNS per hop.
• Live TUI (bubbletea/lipgloss): loss%, sent, last/avg/best/worst/stddev, and a latency sparkline, refreshed continuously.
• Continuous stats with online mean/variance (Welford) and detection of load-balanced paths (multiple addresses per hop).
• Probe protocols: ICMP echo (default) and TCP SYN (--tcp, for paths that filter ICMP).
• Report & JSON modes for one-shot runs and scripting.

Requirements

• Go 1.24+

• CAP_NET_RAW (raw sockets). Either run with sudo, or grant the binary the capability once:

  go build -o mtrx .
  sudo setcap cap_net_raw+ep ./mtrx
  

Usage

mtrx 1.1.1.1                    # live TUI (ICMP echo)
mtrx --tcp -p 443 example.com   # TCP SYN probes to port 443
mtrx --report 10 1.1.1.1        # run 10 cycles, print a static table
mtrx --report 10 --json 1.1.1.1 # emit JSON instead

Flags

Flag	Default	Meaning
-m	30	max hops (TTL)
-i	1s	interval between rounds
-w	1s	per-probe timeout
--tcp	false	use TCP SYN probes instead of ICMP echo
-p	443	destination port (TCP mode)
--report N	0	run N cycles then print a static report (0 = live TUI)
--json	false	with --report, emit JSON

TUI keys

• q / Ctrl-C — quit
• n — toggle reverse-DNS names vs raw IPs

Colour key: yellow = private, orange = CGNAT, red = bogon/reserved.

Architecture

main.go                     flags, target resolution, mode selection
internal/
  prober/                   TTL-sweep probe engines
    icmp.go                 ICMP echo (raw socket, shared reader, seq-matched)
    tcp_linux.go            TCP SYN (raw sockets, checksummed, port/seq-matched)
  session/                  continuous rounds + per-hop stat aggregation
  enrich/
    bogon/                  special-use/bogon longest-prefix classifier
    asn/                    Team Cymru DNS whois resolver + cache
  tui/                      bubbletea live table + lipgloss styling
  report/                   static text + JSON output

Notes & limitations

• TCP SYN mode is IPv4 only for now; ICMP mode supports IPv4 and IPv6.
• TCP traceroute commonly shows more missing intermediate hops than ICMP because many routers do not return time-exceeded for TCP — this matches system traceroute -T behaviour.
• ASN/rDNS lookups are asynchronous; enrichment fills in a moment after a hop first appears.