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.

  • What kind of software do you use on the server? Jan 14 '11 at 3:57
  • I am using pptpd on the server. Jan 14 '11 at 6:11
  • does my answer help? Jan 14 '11 at 6:16
  • Oh I tried it and check the comment bellow your answer. Jan 14 '11 at 6:18
  • 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

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.



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

speed 115200
option /etc/ppp/options.pptpd

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.

  • 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. Jan 14 '11 at 6:17
  • 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 Jan 14 '11 at 6:48

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.