OpenVPN: slow download while tunneling traffic
I have run into a problem w/ my OpenVPN setup and even though I looked very hard, I was unable to find the root cause or a solution for it. So this is kinda my last resort and every hint, clue or help is greatly appreciated.
Let me shortly detail my situation:
I am located in Europe and my server is in Newark, NY. Naturally this results in higher latencies (avg. 115ms). Everything except for mail related traffic/services is only accessible through my OpenVPN setup. I can download backups from my server w/ speeds up to 16 MBit/s and more (tunneled btw). So this is really fine. The problem is when I use my OpenVPN server as a gateway and I route my Internet traffic through it. Download speeds are down to 2 MBit/s and less. Earlier today I made another test. I tried downloading a Gentoo LiveDVD from the same server on the net once directly from my server and once from my client machine tunneled through my server. The result was that the tunneled download was only only a fraction (1/8th) the speed of the download I did directly on my server: ~ 460 kb/s vs ~ 2.7 MB/s. I know that the higher latencies will limit my maximum throughput but receive window scaling should make up for it and besides I can download directly from my server to my client tunneled with full speed.
By the way: I am using OpenVPN 2.1.1 on both client and server via udp (tried tcp, made no positive difference). My server is running kernel 2.6.32-linode23.
Like I said earlier, I would really appreciate any help I can get.
Thanks a lot in advance.
So long,
matthew.
