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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.

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

up vote 0 down vote accepted

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

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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.

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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 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 –  Alexey Shatygin Jan 14 '11 at 6:48
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