TCP Window Size

[Jonb]

I am sure this has been asked but I couldn't find an answer.

I have 1Gb of transit and when connected to the router I max out on a speed test at 780Mbs. When behind the PFsense I only get 280Mbs and I am sure this is a window size rather than anything else as this is a single stream.

Is this something would would be a good idea?
http://www.docunext.com/blog/2009/07/disable-window-scaling-on-pfsense.html

If anyone has expericanced this your thoughts would be greteful.

[johnpoz]

Why would you think that pfsense is altering your window size?

Why don't you just sniff your traffic and see if your client it is using the correct window size.

see attached example - this is running through pfsense - window size has nothing to do with the router(pfsense).  Are you clamping it or running through a vpn?

There are many reasons why pfsense might not be able to give your full wire speed..  I doubt window size is one of them.  What hardware is pfsense running on?

[Jonb]

To be honest the window size was a stab in the dark. I have no idea why it would drop in speed.

The hardware is intel x520 10GB nics with VMware distributed switch. If a plus my laptop before PFsense I get full speed, but I am not over bothered I was more interested in the possible reasons for the slowdown.

[cmb]

The firewall doesn't touch anything to do with TCP windows. Anything you modify in relation to TCP on the firewall only applies to traffic initiated by the firewall itself, which most of the time is nearly nothing.

[Jonb]

Bizza wonder what is causing the slight degrade on speed.