Jukka Salmi --> tech-net (2006-06-15 16:27:45 +0200):
> Hi,
> 
> I'm having problems with [1]vpnc on a laptop when connected to the
> WLAN (ath0):
> 
> - vpnc connects successfully
> - I mount a file system from a SMB/CIFS server through the VPN
> - accessing the smbfs (cd, copying small files) works fine
> - trying to copy a larger file results in a time out message:
> 
> $ cp Test.pdf /tmp
> cp: /tmp/Test.pdf: Connection timed out
> 
> After this I'm unable to interrupt the copy process and to unmount the
> smbfs. Furthermore, shutting down the system hangs forever while trying
> to unmount file systems.
> 
> When the laptop is connected to the LAN (wm0), everything works fine,
> including copying large files through the VPN.
> 
> Any hints what could be the source of this problem or where I should
> start debugging?

AFAICT this turned out to be a MTU problem: the vpnc script set the
MTU of the tunnel interface to 1412 - and packets larger than that
value didn't make it to the other side of the VPN. Setting tun0's MTU
to 1500 fixed the problem. So, who's the culprit?


Regards, Jukka

> [1] http://www.unix-ag.uni-kl.de/~massar/vpnc/

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