How to setup a fast VPN server

Question

I am trying to set up a VPN that has a fast download speed. The server I have is a linux server and from there I can download 2 megabytes a second.

At home I can also download with 2 megabytes a second. All the downloads I do are from the same source, no different server.

Now I have set up a VPN connection between my home and the server, and now I am only downloading 64 kilobytes a second! The connection I have created is a PPTP server on a debian machine.

Now my question is if it is possible to optimize this connection. Should I maybe switch to OpenVPN, or change operating systems? Or are there some kind of settings to tweak to make the connection optimal.

PS. The server I am running is on a XEN node. I have done the proper ip forwarding.

when you say "and from there i can download 2MB/sec" do you actually mean that, or do you mean the server can download from the net at 2MB/sec ? (and by MB i assume you mean megabit, mb). — Sirex, Jan 14 '11 at 12:25
I mean the server can download from the net. And by megabytes i mean megabytes, not bits. — Saif Bechan, Jan 15 '11 at 01:13

Alexey Shatygin · Answer 1 · 2011-01-15T09:00:09.777

1

It could be a speed limitation in /etc/pptpd.conf file. Example of the config:

---cat-/etc/pptpd.conf---
speed 115200
option /etc/ppp/options.pptpd
debug
localip 10.0.0.1
remoteip 10.0.0.2-10
---end-of-cat---

Where the speed line determines the baud-rate.

Look here for more info on the pptpd.conf: http://pwet.fr/man/linux/formats/pptpd_conf

And there is the option, to set the with the key-option (see man httpd for details, or here is the link: http://www.linuxcertif.com/man/8/pptpd/).

Personally, I prefer FreeBSD and mpd4 for my VPN-server purposes, it gives very high-speed results.

edited Jan 15 '11 at 09:00

answered Jan 14 '11 at 04:13

Alexey Shatygin

736
4
11

No it is unfortunately not the speed limit, and I can not find any working tips in the manuals. But thank you for the help. I could not find any information on the 'key-option' you are talking about, can you be any clearer on that. – Saif Bechan Jan 14 '11 at 06:17
key-option it is the parameter you add to a command, when you start it. For example, to set the speed limit to 115200 baud, the command to start pptpd will look like this: pptpd -s 115200 – Alexey Shatygin Jan 14 '11 at 06:48

score 0 · Accepted Answer · answered Jan 14 '11 at 11:31

You're always going to see a slowdown using tunnelling - although I must admit that this is much worse than I'd expected. Factors contributing to the difference between the slowdown I'd expect (~10%) may be due to packet splitting (have you tried tuning the MTU?) and restricted congestion window handling.

An IPSEC based solution should give you near line speeds - although (IME) it can be rather tricky to get this running across NAT / with different endpoint implementations.

HTH

How to setup a fast VPN server

2 Answers2