[Openswan Users] TCP connections stalling

Andy Coates andy at corenetwork.co.uk
Fri Dec 16 14:31:07 CET 2005


Basically the problem we're seeing is in our IPSEC/L2TP setup.  The IPSEC
connection is brought up fine (tunnel), and L2TPd acting as a client
connects to the remote gateway over the IPSEC tunnel fine.  ppp0 comes up
and we're given an IP address, everything looks fine (each end pingable).
This is all following the guide at

What happens though is during a telnet session to a device on the remote
network the connection seems to "stall", and then the tcp connection is
dropped when you try anything to bring it back (hit enter etc).  This can
happen anywhere from 1 minute to 10 minutes into the session, it just seems
to stop receiving packets from the remote network.  When this happens, I can
reconnect the telnet session fine so no problems on the IPSEC tunnel or L2TP
tunneling, just seems to drop TCP connections.

Both sides are running OpenSWAN, L2TP and PPP.  I'll have to get the remote
network's versions but I believe we're both running 2.6 kernel using NETKEY
(at least 2.6.13) with OpenSWAN 2.4.3.

Does it sound like any common problem seen before?

Thanks in advance,

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