Slow File Copy Issue across vpn tunnel

[Chuck.Reimer]

I am copying a 5 meg file across a permanent tunnel (vpn) from server A (behind a UTM-1 running NGX R65) to server B (behind a Nokia IP380 running NGX R65).

The issue I am having is when I copy the file (power point files seem to be the worst) the copy window on server B pops up about 4 minutes after I have clicked paste.

The reverse is true on the other end of the tunnel. When I click Paste on server A the copy window appears immediately, but when the copy hits 0 seconds remaining it waits 4 minutes and then finishes the copy.

The UTM-1 has a 10/1 internet connection.

The IP 380 has a 9/2 internet connection.

My guess is there is some kind of caching issue on the IP 380 but I am at a loss finding it.

Does anyone have any ideas?

[melipla]

Its a known issue. Taken from sk32651, issue this [SPLAT] command to the NGX gateway(s):
fw ctl set int fwtcpstr_max_window 65536

That setting won't survive reboot, but if it fixes your problem, edit the $FWDIR/boot/modules/fwkern.conf file (create a new one if it doesn't exist) and add this line:
fwtcpstr_max_window=0x10000

Which should set the parameter after each boot. Took me forever to solve that one. Be aware that changing that parameter affects the performance of Smart Defense, which is the primary reason why its not "fixed" by default.