[c-nsp] trace via gre over ipsec tunnel

[Gert Doering]

Hi,

On Tue, Feb 15, 2005 at 03:21:14PM +0300, vladimir.savostin at eu.effem.com wrote:
> We have following network configuration: 
> Host1--Router1--(GRE/IPSEC tun)--Router2--(GRE/IPSEC tun)--Router3--Host2 
> 
> When doing traceroute from Host1 to Host2 I see the following results: 
> 
> Tracing route to Host2 over a maximum of 30 hops 
> 1 <10 ms 10 ms <10 ms Router1 
> 2 <20 ms 20 ms <20 ms Host2 
> 
> The problem is that tun interfaces don't seen as hop counts. 
> There are no some special configuration on tun interfaces. 
> 
> May be some of your faced with such problem early? 

There are a number of interesting IOS bugs where the TTL isn't decremented
on packets being CEF-switched through GRE tunnels.  All bugs I know 
(read: that I've seen in our network) have been fixed in recent IOS
versions.

What IOS versions are you using?

gert

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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de