ICMP redirect (was Re: Patch for route.c)

Gerd Knorr (kraxel@cs.tu-berlin.de)
Tue, 8 Apr 1997 21:30:15 +0200

In article <199704081647.JAA22936@cesium.transmeta.com>, you wrote:
>A single physical network can have any number of gateways connected to
>it. Hosts on that network need to know where to send their packets
>that are going off the net. One way that can be handled is by relying
>on ICMP REDIRECT, which is, in a sense, the simplest routing protocol
>on the Internet. If so, the default route should be set to a host
>(typically a router) which would know the proper route; in order to
>avoid redirects in the common case you would typically pick the most
>frequented router.

What does the kernel with ICMP REDRECT packets? A while ago I had the syslog full
of kernel messages about received icmp redirect messages. This was probably becauce
our network admins have changed the network setup (switched to switched ethernet,
with a larger netmask), after reconfiguring interface and routing according to the
changes the messages are gone.

I'm just intrested what happens there. It looks like the kernel receives and respects
icmp messages (but does not print them): If I do a traceroute, the first hop is
_not_ allways the default gateway, but another router on the net. I have static
routing (no gated or so), with four enties: lo, eth0, class D (multicast) on eth0,
default gateway. kernel is 2.0.29.


Gerd Knorr <kraxel@cs.tu-berlin.de> |  Where these funny chars come from ???
http://www.cs.tu-berlin.de/~kraxel/ |  [ ... ] Aha, the debug code is broken!