Traceroute in 15 lines of code using Scapy

Pretty nifty. One of the things traceroute also does is to deal with broken routers that don't send the proper replies, as well as a number of other edge cases, but this is a cool toy and will probably work in most average cases.

see also:

http://cluepon.net/ras/traceroute.pdf and http://blog.cachefly.com/2012/02/15/understanding-traceroute...

I've just started using scapy recently. The syntax is a little inconsistent, but it's really powerful. It defines a domain-specific language (DSL) that piggybacks on python syntax. You can make a traceroute-like object in one line:

  pkt = IP(dst=target, ttl=(4,25),id=RandShort())/TCP(flags=0x2)

This single pkt object describes 22 IP packets, each with a TTL from 4 to 24 inclusive. Each IP packet encapsulates a TCP packet with the SYN flag set.

http://www.secdev.org/projects/scapy/doc/usage.html#tcp-trac...