[Gllug] Path MTU and multiple layers of NAT -- bad?

[Daniel P. Berrange]

On Wed, Feb 08, 2006 at 02:39:58PM +0000, Richard Jones wrote:
> 
> I've got a strange case where I can't fetch web pages from a remote
> server.  I can ping the server, I can connect to the remote server,
> but after that the connection hangs until close.
> 
> The difference seems to be that (for various reasons) I'm trying to
> connect over multiple (3) layers of NAT.  My best guess is that path
> MTU discovery is screwed up somehow.

> Any ideas or further things I can try?

Having PMTU disocvery enabled, means that all packets will be sent with
the DF bit set, so to test if this is the problem temporarily disable 
PMTU and let the packets fragment normally.

  echo 1 >  /proc/sys/net/ipv4/ip_no_pmtu_disc 


Regards,
Dan.
-- 
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