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I'm currently in the situation of attempting to setup OpenVPN on a personal VPS, for connection primarily through an overly restrictive firewall. All of the setups mentioned below work when used through a reasonably-firewalled connection.

I have tried:

  1. OpenVPN running on the standard port
  2. OpenVPN running on port 443 (I start OpenVPN manually from the command line on the VPS and see that the server reports the connection being closed almost immediately, I assume this is a result of DPI on the firewall)
  3. STunnel running on port 443 to access OpenVPN and evade DPI. This is the most successful and allows a connection and internet access through the VPN for ~10-20 seconds, before the connection is forcibly closed.

Is there anything else I can attempt?

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Dear lord, what "personal VPS" provider do you have that goes to such lengths to prevent you from running a VPN?! Also, it isn't clear if you are trying to use the VPS as an OpenVPN server, or if you want to make it the client? –  ÃŁŁǫǛȉЖΦΤїҪ Sep 25 '12 at 20:42
    
Woops! I should have been more clear. The VPS provider is Linode, and they definitely aren't blocking anything. ;) The problem is that I'm connecting to the VPN from a client (my laptop) whose internet access is severely firewalled. –  R.L. Stine Sep 25 '12 at 20:52
    
A VPN solution in general is going to be fairly easily detected by anything that does stateful packet inspection, as you hinted. The forceful disconnection could be due to traffic analysis methods looking at the https connection of stunnel and going "wait a minute, standard HTTP request/response connections aren't nearly that chatty!" -- in essence you are stuck. You could try an HTTPS proxy though; maybe something where you pass the request as an HTTP body (over SSL) to a servlet and it forwards your request... o_O –  ÃŁŁǫǛȉЖΦΤїҪ Sep 25 '12 at 21:07
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You may want to keep in mind that bypassing restrictions implemented by a company firewall are likely a violation of company policy. I suggest you talk to the firewall admin about the issue. –  Ansgar Wiechers Sep 25 '12 at 22:57
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2 Answers

Connections being cut off after a length of time sometimes indicate a bytes-per-second type of limit. Try seeing if slowing down your VPN connection works. Also if you have OpenVPN configured for UDP try TCP (443 UDP may be blocked whereas 443 TCP may go undetected).

Visit a well known site that uses SSL and check the certificate. Then do the same at home. If they don't match then your location is using a transparent HTTPS SSL proxy and can actually see your HTTPS traffic.

It's possible something that isn't port 443 isn't watched so closely. Try 22.

It may sound stupid but try doing it over port 80 and see what you get. You also may try setting up an HTTP tunnel between you and the VPS to make the traffic look like HTTP requests.

If you are feeling insane, try iodine.

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+1, but especially for iodine! –  0xC0000022L Mar 22 '13 at 21:56
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I've never tried it (so lemme know if it works!) but give a shot @ using ssh tunneling over 443 and run your OpenVPN through the tunnel. You may need an extra remote host to listen on 443 if you don't have one but there is an example here http://www.anonyproz.com/openvpnsshtunnel.pdf for using their proxy service, but this is also googlable https://www.google.com/webhp?sourceid=chrome-instant&ion=1&ie=UTF-8#hl=en&tbo=d&sclient=psy-ab&q=ssh%20tunnel%20openvpn&oq=&gs_l=&pbx=1&fp=dfe86ec64229ab6&ion=1&bav=on.2,or.r_gc.r_pw.r_cp.r_qf.&bvm=bv.41018144,d.b2U&biw=1920&bih=979.

I've also known people to use this approach as a proxy b/c their employer blocked access to job sites such as dice.com back when they were popular..

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