[Openswan Users] IP Truncated

[Jacco de Leeuw]

Oliver Tomkins wrote:

> When our remote users connect everything seems fine,  however when  they 
> try to connect to one of our applications it fails.
> 
> tcpdump tells us this:   
> 
> 15:27:59.571219 IP ipsec.domain.co.uk.l2tp > XXX.XXX.XXX.XXX.l2tp: 
> l2tp:[L](2/1) {IP truncated-ip - 742 bytes missing! 
> dbs.domain.co.uk.ms-sql-s > client.domain.co.uk.1161: P 2358:3571(1213) 
> ack 1116 win 64420}

Tcpdump may be truncating the packets. Can you try with a larger snapshot
length (e.g. -s 1500)? Are you using KLIPS or NETKEY? In the latter case,
using tcpdump does not make much sense because of the way how NETKEY works.

There could be an MTU problem. There are known problems with PMTU discovery
in 2.6 kernels before 2.6.12, see also:
http://www.jacco2.dds.nl/networking/freeswan-l2tp.html#MTUproblems


Jacco
-- 
Jacco de Leeuw                         mailto:jacco2 at dds.nl
Zaandam, The Netherlands           http://www.jacco2.dds.nl
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