[Fedora-xen] scp in FC6 + Xen gets stuck in "stalled" stage

[Ranganathan, Shobha]

Yes . That did it. I am able to copy files using scp.

Why does an MTU issue come up in this scenario ? 

Thanks
Shobha
-----Original Message-----
From: Paul Wouters [mailto:paul at xelerance.com] 
Sent: Wednesday, November 15, 2006 1:25 PM
To: Ranganathan, Shobha
Cc: fedora-xen at redhat.com
Subject: Re: [Fedora-xen] scp in FC6 + Xen gets stuck in "stalled" stage

On Wed, 15 Nov 2006, Ranganathan, Shobha wrote:

> I am trying to get scp to work. It gets stuck displaying "stalled"
> message.

> This happens in the Xen that I built with xen-3.0.3-rc3 which builds
it
> with 2.6.16.29 kernel in Fedora Core 6.

> I boot into Fedora provided   FC6 Xen host and tried scp and it works.

Looks more like an MTU isuse. Try using clamping:

iptables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS
--clamp-mss-to-pmtu

Otherwise, try pinging with different size packets until it fails, and
then use
the last successful packet size (eg 1440) to:

iptables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss
1440

Paul