What *is* source routing?
Soure routing is an IP option which allows the originator of a packet to specify what path that packet will take, and what path return packets sent back to the originator will take. Source routing is useful when the default route that a connection will take fails or is suboptimal for some reason, or for network diagnostic purposes. For more information on source routing, see RFC791. Unfortunately, source routing is often abused by malicious users on the Internet (and elsewhere), and used to make a machine (A), think it is talking to a different machine (B), when it is really talking to a third machine (C). This means that C has control over B’s ip address for some purposes. The proper way to fix this is to configure machine A to ignore source-routed packets where appropriate. This can be done for most unix variants by installing a package such as Wietse Venema,
