Is there a way to send out a packet such that its path is predetermined? Basically, I want to attach an "IP map" of how I want it to travel. If so, what are the steps?


  • That actually defeats the purpose of IP, which is to automatically route around damage. IP was an experiment funded by the DoD to maintain communications in the event of war, where the traditional circuit-switched infrastructure is susceptible to being damaged and not working.
    – Ron Maupin
    Commented May 8, 2019 at 19:38

2 Answers 2


What you are describing is IP Source Route. However, any network with even a hint of security will have source-route disabled. But if you want to try it anyway, keep in mind there's a limit to the size of an IP header, and thus, a limit to the number of hops you can specify.

  • Worth mentioning that IP source routing is on by default in IOS. Readers should disable it on their Cisco boxes if they have not already done so Commented Apr 28, 2014 at 21:52
  • I went to the wikipedia article on IP source routing and read that there's strict source & record routing (SSRR) and loose source & record route (LSRR) and that LSRR is the one that's blocked on many routers. So am I correct in thinking that SSRR will likely still work?
    – lynvie
    Commented Apr 29, 2014 at 3:41
  • 1
    The wiki article is sparse and incorrect. no ip source-route turns off all ip header source routing on Cisco gear. (and everybody else clones that behavior) The accept_source_route flag in linux also affects both strict and loose source-route options.
    – Ricky
    Commented Apr 29, 2014 at 4:06
  • So it sounds like it's not really possible. The closest thing is just a passive traceroute approach. Too bad! Thanks for the info.
    – lynvie
    Commented Apr 29, 2014 at 21:11

You can use ping with the -j (loose source) or -k (strict source) option to send such a packet. Just keep in mind that this feature is normally disabled on routers for security reasons.

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