traceroute / traceroute6

Overview

traceroute maps the IP path toward a destination by sending packets with increasing TTL and reading ICMP time-exceeded replies. Useful for locating where latency or loss begins.

Syntax

traceroute [options] host
traceroute6 [options] host
# Ubuntu often ships `traceroute` or `tracepath` / `mtr`

Common Options

Option	Description
-n	No DNS reverse lookups
-w wait	Per-probe timeout
-q n	Probes per hop
-m max	Max hops
-I	ICMP probes (vs UDP default on some builds)
-T	TCP probes (firewall-friendly sometimes)
-p port	Base port

Examples with Explanations

traceroute example.com
traceroute -n 1.1.1.1
traceroute -T -p 443 example.com
traceroute6 -n ipv6.google.com

Friendlier alternatives

tracepath example.com      # often no root
mtr -rwzc 50 example.com   # live + report (install mtr)

Notes

• Firewalls may drop probes → * * * hops.
  
• Not all hops respond; interpret carefully.
  
• Cloud networks may hide internal topology.

Related Commands

• ping — reachability/latency to end host
  
• mtr — continuous traceroute
  
• ip route get — local routing decision
  
• dig — ensure name resolves first