Scp traffic stalling

[helpdeskadam]

When I try to transfer a file using scp from office A to office B using pfSense as default gateway the transfer will stall leaving an incomplete file on the receiving end which is exactly 48k. Interrupting the stalled transfer and immediately trying again will succeed.

We have pfSense configured with three interfaces (all bce). It is also the default gateway for all machines in the LAN. Routes are configured on the box for traffic to other branch offices. All checksum offloading has been disabled. pfSense is configured for bypassing traffic on the same interface.

Circumventing pfSense by adding a route on office A's server to office B's LAN using the VPN router directly (which is also in the LAN) works without any problem.

I have been tinkering with kernel MTU parameters, but to no avail.

We are running 2.0-RC1 (amd64) built on Sat Feb 26 18:07:23 EST 2011. This is an in place upgrade from 1.2.3-RELEASE built on Sun Dec 6 23:21:36 EST 2009.

I'm posting this as a new topic, but there are similarities to a previous thread (http://forum.pfsense.org/index.php/topic,33709.0.html).