On 2018-05-02 Martin Pieuchot <m...@openbsd.org> wrote: > On 02/05/18(Wed) 11:47, Christopher Zimmermann wrote: > > I just want to bring this up again. Can some network guru give me an ok > > or some feedback please? > > Can you explain with words why we shouldn't send a redirect? The > comment above your diff states clearly: > > "If forwarding packet using same interface that it came in on, > perhaps should send a redirect to sender to shortcut a hop." > > So you're suggesting no to do that, why?
That's not exactly what I'm suggesting. In this setting: A 192.168.4.7 <--> 192.168.4.1 Gateway 192.168.1.1 <--> 192.168.1.2 B I observed this senseless redirect: 192.168.4.1 > 192.168.4.7: icmp: redirect 192.168.1.2 to host 192.168.4.1 in plain language it means: "Hi 192.168.4.7, I'm 192.168.4.1. You sent me a packet for 192.168.1.2. I'm not the best route, next time send it to 192.168.4.1." So the gateway is instructing host 192.168.4.7 to use gateway 192.168.4.1 instead of 192.168.4.1. (this is not a typo!) I'm suggesting to skip the redirect when we would redirect the sender to an(other) address of the very interface the original packet came in on. I hope this explanation is reasonable. Christopher -- http://gmerlin.de OpenPGP: http://gmerlin.de/christopher.pub 2779 7F73 44FD 0736 B67A C410 69EC 7922 34B4 2566
