[Openswan Users] (p)mtu problem between winxp and openswan2.3.0

[VRZ (VRZ Koblenz)]

hallo,

i am using openswan 2.3.0 under suse9.3 (kernel 2.6.10).  If i start a
connection from my winxp pro workstation (sp2) via adsl a vpn-connection
every thing works fine until i start a vnc-session. Then the screen is
frozen and nothing works. This is a classical (p)mtu-prohlem as i read
but until now i haven'f found any solution for this problem.

Here is  what i did:

Under windows xp the largest packet i can ping without defragmentation
is 1395 bytes (ping -f -l 1395 xx.xx.xx.xx). The mtu of my linuxbox is
1492 bytes. I am tuning via iptables the mtu:

#iptables -A FORWARD -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS
--set-mss 1452
iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS
--clamp-mss-to-pmtu

none of them fixed the problem.

During the session setup my linux box writes the following message to
the systemlog:
kernel: pmtu discovery on SA ESP/54c693d0/54a99ca9

Do you have any suggestions?




Regards from germany
Frank

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.openswan.org/pipermail/users/attachments/20050330/5399bec3/attachment-0001.htm