openvpn only using half of my upload bandwidth???
 

i have an openvpn setup that is hosted on a 50mpbs down/10mbps up comcast business connection. doing a test transfer of files from the vpn server to another machine on the same LAN results in near-wireline speeds (gigabit network, realistic throughpu is ~950-990 mbps). But when connecting over the internet, transferring files from the local LAN to teh remote client is a terribly slow 3-4mbps? I don't understand why... it can't be the CPU speed or anything on the VPN server, and if I setup a test FTP server unencrypted, I can max out my upload bandwidth perfectly with that. Please help, I've been so close to having a perfect VPN setup for months now but have gotten zero ideas as to why it's so slow.... I have played around with mssfix/fragment options (tried 1428,1400,1300,1200) but of course that had absolutely no effect.

You are saying it can't be the CPU on the VPN server but still it would be the first thing I check.
After that speed check the link with a UDP based transfer (you can use nc or mz). Check it using the ports you use for your VPN setup - this should expose any trafic shaping on the link.
I guess the MTU on the VPN server will be adjusted automatically so this shouldn't be a fragmentation issue, but may be worth a look.

That's all I can think of atm :)

Nik

fyi the cpu is an intel core 2 duo 2.4GHz... i would guess that this is more than enough, considering openvpn apparently can run on el cheapo linksys routers...

so more info....

i've narrowed it down to what seems like a wifi issue. when I connect on an ethernet connection on the remote end, I can get normal bandwidth transfers (~9.6mbps, or 1.2MB/s) but when I'm on a wifi connection (even if its a fast 35mbps down with no one but me using it) I get my bandwidth cut in half, maxing out at around 3-4mbps. is this normal? surely just the act of being on wifi shouldn't reduce my bandwidth by 50%?

no suggestions at all?

i have since tried an entirely different computer as the openvpn server... core i3 3.3GHz 4GB DDR3 RAM. Not a thing has changed. SO it can't be the cpu.

even more updates:

tried removing the router entirely and going directly from the VPN server to the cable modem. Obviously I couldn't access the rest of the LAN, but a remote connection into the VPN server and a subsequent iperf test from a connected client to the server yielded 2.85 megabits per second, where the client was on ethernet on a 25mbps down connection.

so i've ruled out the router as well. i'm about to give up...