Nmap Development mailing list archives

Re: [PATCH] Report ICMP TTL Exceeded messages


From: Brandon Enright <bmenrigh () ucsd edu>
Date: Tue, 6 May 2008 21:26:25 +0000

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On Fri, 4 Jan 2008 23:13:07 -0800
Fyodor <fyodor () insecure org> wrote:

On Sat, Jan 05, 2008 at 02:22:36AM +0000, Brandon Enright wrote:

The output looks something like:

ICMP TTL Exceeded message when sending to X.Y.147.215, possible
network loop, try increasing TTL with --ttl

Have you (or other people) actually seen many cases where increasing
the TTL with --ttl resolves the problem?  If so, we could increase the
default Nmap TTL.  But I figured it was high enough that TTL exceeded
notices are probably due to loops which would simply loop more with a
higher TTL.

Cheers,
-F


I have re-worked this patch (attached) to reduce the verbiage printed
to just:

Got ICMP TTL Exceeded when sending to 1.2.3.4, possible network loop!

The error() message is limited to one printing per host so that the
screen isn't flooded with useless information.

The patch applies cleanly against SVN.

Brandon

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