April 8, 2026
Packets, parrots, and pedants
Understanding Traceroute
Geek fight over an internet map tool: “use mtr”, “actually” lectures, and a parrot tale
TLDR: A dev explains traceroute by showing how packets “expire” hop by hop and built a Rust version to prove it. Commenters immediately sparked tool wars (mtr and tracepath), dropped “actually” corrections about how big routers work, and even shared a parrot-and-shotgun legend—equal parts lesson and lore.
A coder rewrote the classic “find the path to 8.8.8.8” trick in Rust and explained the magic behind traceroute: it sends messages that intentionally “expire” step by step so each router yells back “time’s up,” revealing the path. The code is neat, but the comments? Absolute theater.
One commenter swooped in with the classic “Actually…”: routers aren’t lazily dropping error messages to save power; big carriers use special chips (ASICs) to move most traffic fast, and oddball packets get slower treatment. Meanwhile, the tool war ignited: fans chanted “just use mtr,” the souped‑up mashup of ping and traceroute that shows live stats (homepage, Cloudflare explainer). Linux folks flexed that tracepath often works without admin powers thanks to a clever error‑queue trick, and a builder bragged they whipped up an AI‑assisted “IP intelligence” toy that traceroutes in under a second.
For comic relief, someone remembered a legendary Usenet yarn about traceroute, parrots named Polly, and shotguns. The vibe: curious newbie energy meets veteran nitpicks, with a side of “rewrite it in Rust” meme and practical tool tips. If you came for code, you stayed for the hot takes, the nostalgia, and the parrot with an attitude.
Key Points
- •Traceroute discovers network paths by sending packets with increasing TTL values and collecting ICMP Time Exceeded replies from each hop.
- •The article shows a real traceroute to 8.8.8.8, illustrating hops through a Tailscale gateway, home router, ISP nodes, and Google DNS.
- •A Rust example sends UDP probes to port 33434 with specified TTLs and listens on a raw ICMP socket for responses.
- •Routers decrement TTL; when it reaches zero, they drop the packet and return ICMP Time Exceeded, revealing the router’s IP.
- •The implementation prints hop IPs or “*” on timeout and stops when the destination IP is reached or the TTL limit is met.