[Openswan Users] MTU issue

[Antony Gelberg]

Hi all,

I have a PMTUD issue with my VPN.  It manifested itself here:
http://lists.samba.org/archive/samba/2005-September/111079.html

This makes sense.  When I ping a LAN host from the roadwarrior, with DF
set, 1450 responds with Fragmentation required but DF set, 1350 responds
normally, but 1400 times out.  As if that wasn't enough,
http://lists.openswan.org/pipermail/users/2004-July/001514.html confirms
my suspicions.

However, I can't seem to find the correct settings.  On the Openswan box,
both WAN(eth0) and LAN(eth1) have an MTU=1500.  I am disregarding the
ipsec0 MTU of 16260 as I believe it's a red herring.  Both routers (LAN
and roadwarrior) have MTU=MRU=1458 and MSS=1418.

However, even if I set MTU=1458 on eth0 and eth1 on the Openswan box, no
joy.    The ping problem is still present.

Hope someone can shed some light.

Antony