On Sat, 4 Dec 2021, Kurt Jaeger wrote:
Hi!
We (AS12502) recently upgraded one router from 12.2.x to 13.0.x. This
caused some surprising effect, with the router sending out
icmp redirects to 0.0.0.0 over multiple hops:
Example:
inet ------ wan:rtr1:lan ------ rtr2 ------ wan:host
x.x.x.1 y.y.y.1
host sends a packet to z.z.z.z and receives an icmp redirect from x.x.x.1
like this:
10:20:16.889185 IP x.x.x..1 > y.y.y.1: ICMP redirect z.z.z.z to host 0.0.0.0,
length 48
whoops.
This has been stopped by net.inet.ip.redirect=0 on rtr1, but my question is:
Why is rtr1 sending those multi-hop icmp redirects at all ?
Could you elaborate on:
(a) Do rtr1 or rtr2 have a default route or are they carrying a full DFZ
without default route?
Assumption: if both rtr2 and rtr1 are running 13 and not 12, rtr2
does have a default route and rtr1 has a full DFZ only and no
default route?
(b) At the time this happens does rtr1 have a route to z.z.z.z ?
route -4 get z.z.z.z
/bz
--
Bjoern A. Zeeb r15:7
