I use VPN quite often in public places where I don't want anyone to read my web traffic. However, some public places have firewalls that block ports required to establish a VPN connection (I usually use PPTP). I don't think some public places (especially my school) really distinguish between a VPN connection and HTTP(S) connections. They just block some ports (I think my school is blocking every port except 80, yes even HTTPS!, but I'm not quite sure.).
So I wonder if I can bypass the firewall (maybe by using another port). I can even change the protocol if necessary.
I already use port 80, and 443 for apache and 20, 21, and 22 for FTP, SFTP and SSH on my VPN server. I can use as many domains as necessary but I only have one IP address. Can configure my server so that it uses port 80 for apache if the requests comes from a specific domain and uses port 80 for my VPN server if it comes from another domain.

The Server is running on Mac OS X Mavericks (a UNIX system) using Mac Server 3.

  • 1
    You've come to the wrong place to ask questions about circumventing network security measures as many of us are the admins that put those measures into place.
    Jun 12, 2014 at 2:30

2 Answers 2


You could try OpenVPN running on UDP on port 53, 80, or even its default port. Many firewalls are not configured to block UDP, and you can have both a UDP service and a TCP service on the same port number.

Can configure my server so that it uses port 80 for apache if the requests comes from a specific domain and uses port 80 for my VPN server if it comes from another domain.

No. The operating system doesn't know anything about domains, only IP addresses, protocols, and ports. So when a packet comes in for port 80 on a certain IP, it looks for what application is listening for TCP on port 80 on that IP, and delivers the packet to it. Only one application can be on any given IP/Port/Protocol set.

If you had multiple IPs, you could run your VPN on one IP and the webserver on another IP. Otherwise, ports are what are used to distinguish between applications.

  • Couldn't he use port forwarding to perform the port 80 splitting he desires.
    – schroeder
    Jun 11, 2014 at 19:50
  • Port forwarding has no way to separate an HTTP request from a VPN request.
    – David
    Jun 11, 2014 at 20:33
  • But he doesn't need to inspect requests, only the source address. Should be possible with ipfw?
    – schroeder
    Jun 11, 2014 at 20:38
  • Assuming a source address or source addresses could be identified, then yes, that could be done. But the OP included "some public places", so probably don't know all the IPs in advance.
    – David
    Jun 11, 2014 at 20:44

There are four main types of VPN - PPTP, L2TP over IPSec, IPSec aka. Cisco IPSec and SSL. As you have stated your IT department appears to be blocking the first three types.

However SSL VPN connections look to your network just like any other SSL traffic and as SSL is used to access secure websites it generally cannot be blocked over zealous network admins.

Therefore you need to look at setting up a SSL VPN system instead.

Note: You cannot use the built-in Apple VPN client to connect to an SSL VPN server. Generally the SSL 'client' is either a Java application or provided by the maker of the SSL VPN server, e.g. Cisco, SonicWALL, Juniper, etc.


  • Four main types? I'd say that OVPN is pretty prevalent. It should also be mentioned that your wording about IPSec is a bit misleading as it's not proprietary to Cisco - Cisco has a VPN solution based off IPSec, but so do other vendors.
    Jun 12, 2014 at 2:29
  • I quoted this answer from the src I mentioned :) I don't take credit for it
    – AK_
    Jun 12, 2014 at 11:22

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