[Openswan Users] Problem with large packets

Herbert Xu herbert at gondor.apana.org.au
Fri Sep 10 08:35:15 CEST 2004

Martin Wickman <martin at wickman.com> wrote:
> I changed the MTU on my local machine to match the NAT-router I am using
> (ADSL with MTU 1454) using 'ifconfig eth0 mtu 1454'. That made it
> possible to _send_ any packets without any problems. Problem is that I
> can only receive packets smaller than (I think) 1325 bytes from the
> office network. Trying anything larger than that results in a stalled
> connection. I'm stuck.
> 1. Any ideas how I can fix this?

If you can't lower the MTU on the other side of the IPsec tunnel, then
the best thing to do when you've got an ICMP black hole is to clamp
MSS on this side.

Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert at gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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