ICMP redirect ignored

Matthias Suencksen (msuencks@techfak.uni-bielefeld.de)
Sat, 25 May 1996 15:55:57 +0000


Hello,

i got two occurrences of "ICMP redirect ingored". I do not know
whether it is a kernel issue, bad configuration or just a network error.
I am linked to the internet via unversity (PPP, ascend terminal server).

1) During a netscape news session (which worked ok) the news host
stopped responding, then the line was dropped:

From the message log:
May 25 15:05:11 nostromo kernel: icmp: ICMP redirect ignored.
dest = 81460437, orig gw = 8146255A, "new" gw = 8146041D, device = lo.
May 25 15:05:12 nostromo last message repeated 2 times ^^^^^??
May 25 15:07:12 nostromo last message repeated 3 times

My inet-addres was 129.70.37.90 (8146255A)
My gateway was 129.70.4.29 (8146041D)
newshost was 129.70.4.55 (81460437)

Why does the kernel print the addresses in hex? Kernel was 1.99.7

2) An other host, which sits on an ethernet. On the ethernet theres is
one gateway (A) to the internet, and another (B) to the university.

By error, I set up just a defaultroute to the first gateway (A).
When I tried to reach a university host X.Y.Z (which worked), the
message logged was flooded with messages like ...

icmp: ICMP redirect ignored.
dest = X.Y.Z , orig gw = X.Y.Z, "new" gw = X.Y.Z, device = eth0

The (A) gateway was a cisco i think, but i am not shure.

I wonder why there is alway the same address(X.Y.Z) ...? I soon figured
out there was a second gateway.
When I set up a route for all the university
hosts to use gateway (B) the ICMP redirects ignored went away.

So far, so good, but my question is: why didn't the kernel accept the
redirect from the gateway (A). It happended with kernel 1.3.93

In one post on "ICMP redirect ignored" I read this was due do IP
masquerading,
but I am not using it (though it is build into the kernel for later use).

Mattias