[vpnc-devel] "packet too short" message

[Alessandro Suardi]

On Mon, 28 Feb 2005 07:05:47 +0100, Maurice Massar
<massar at unix-ag.uni-kl.de> wrote:
> hi,
> 
> On Sun, Feb 27, 2005 at 05:14:30PM +0100, Alessandro Suardi wrote:
> > tcpdump: listening on wlan0, link-type EN10MB (Ethernet), capture size 96 bytes
> > 16:42:46.809020 IP (tos 0x0, ttl 114, id 21504, offset 0, flags
> > [none], proto 17, length: 29) 193.32.x.xx.4500 > 192.168.1.6.4500: [no
> > cksum] UDP, length 1
> ...
> > It's very easy to see that the packets triggering the message are the ones
> >  with length=1, no flags, no cksum, as these packets come in from the
> >  VPN server even when I'm doing nothing, so matching the tcpdump
> >  output and the syslog messages is a piece of cake :)
> 
> ah.. I remember. These packets are defined in the NAT-T RFC to keep the
> NAT mapping alive, so it is safe to just ignore them (and maybe vpnc
> should send them too...)

OK. For the time being I modified the test to only print out
 packets where r != 1 and encap->fixed_header_size != 8,
 and so far I have none.

Thanks,
 
--alessandro

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