Routing problem (not related to Red Hat)

[Joseph Teo]

Hi,   I was wondering if you guys are able to help out with a conceptual problem.   Question:  What does a router do, if it discovers that it is about to route an IP datagram back over the same network interface on which the datagram arrived?   I'm guessing a ICMP redirect message would be sent back to host.. but i'm not 100% sure about this.   Any heap appreciated.