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Very poor preformance

Posted: Tue Apr 12, 2011 9:44 pm
by spirre
Hi,
I have a ubuntu 10.10 with openvpn 2.10 installed from apt-sources.
On my client (Windows 7) i have openvpn 2.1.4.

The problem is that i get very poor preformance from my vpnserver, maxium 3MB/sec and without VPN i get 9MB/sec from same server/trying downloading same file.

UDP
TAP
Cipher none and AES-128-CBC tested.
MTU 1500 and 1400

Any ideas?

Re: Very poor preformance

Posted: Wed Apr 13, 2011 8:01 am
by janjust
the performance of openvpn on windows can be a bit poor, but you should be able to get more than 33% of the linkspeed; if your setup is udp based then try adding

Code: Select all

fragment 1400
mssfix
to see if it makes a difference; altering the tun-mtu size on the windows client does not do much unless the tap-win32 mtu size is also altered. You can find the optimum mtu size by running

Code: Select all

ping -f -l <packet size> <remote-host>
For a "regular" ethernet link the largest packet you can send is 1472 bytes, which results in a MTU value of 1500 (the default).
If you find that the largest packets you can send is 1440 bytes then choose 1468 as the tun-mtu size.

Re: Very poor preformance

Posted: Wed Apr 13, 2011 8:13 am
by spirre
Hi,
Thanks for the reply, ofcourse i have changed the mtu on tap device on the clientside to..
Didnt do shit.. :)

mssfix i already have. will try fragment.

Thanks

Re: Very poor preformance

Posted: Wed Apr 13, 2011 7:25 pm
by spirre
Didnt do anything with fragment 1400 and msfix.
any more idea?