This document explains how to set up an Apache server and SSH client to allow tunneling SSH over HTTP(S). This can be useful on restricted networks that either firewall everything except HTTP traffic (tcp/80,tcp/443) or require users to use a local (HTTP) proxy.
A lot of people asked why doing it like this if you can just make sshd listen on port 443. Well, that might work if your environment is not hardened like I have seen at several companies, but this setup has a few advantages.
You need: Here is an example configuration file for Apache (/etc/httpd/conf.d/ssh.yourdomain.com.conf) that allows access from 2 dialup IP addresses (customer location) to machine1.yourdomain.com and machine2.yourdomain.com.

<VirtualHost 10.1.2.3> DocumentRoot /var/www/html Customlog ssh.yourdomain.com-access.log combined ErrorLog ssh.yourdomain.com-error.log HostnameLookups On ProxyRequests on AllowCONNECT 22 2022 ProxyVia on ### Deny everything by default <Proxy *> Order deny,allow Deny from all </proxy> # <Proxy 123.45.67.89> # <Proxy machine.yourdomain.com> # <ProxyMatch .*\.yourdomain\.com> <ProxyMatch (machine1|machine2)\.yourdomain\.com> Order deny,allow Deny from all ### External (customer) sites allowed to connect Allow from 194-78-234-211.dialup.skynet.be Allow from 114-149.241.81.adsl.skynet.be </ProxyMatch> </VirtualHost>

Download 1.6.0. It includes a patch I wrote to chain 2 HTTP proxies. ()

Then add something similar to this to you ~/.ssh/config file.

Host *.yourdomain.com *.otherdomain.net someserver.org DynamicForward 1080 ProxyCommand proxytunnel -v -p proxy.local.net:8080 -r ssh.yourdomain.com:443 -d %h:%p -H "User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Win32)\n" ServerAliveInterval 30

This will make SSH use the proxytunnel utility to tunnel SSH over HTTP(S). After that you can simply do:

[user@localhost ~]$ ssh machine1.yourdomain.com Connected to proxy.local.net:8080 Tunneling to ssh.yourdomain.com:443 (destination) Starting tunnel user@machine1.yourdomain.com's password:

Download 1.6.0. (For Windows take the cygwin build) It includes the patch I wrote to chain 2 HTTP proxies. ()

Then to configure putty to use proxytunnel, you need a recent putty (newer than 0.58). Currently only the development release includes the required functionality.

Then go into the Connection > Proxy menu. Select the Local proxy type. And then provide as Telnet command, or local proxy command the following line:

proxytunnel -q -p proxy.local.net:8080 -r ssh.yourdomain.com:443 -d %host:%port -H "User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Win32)\n"

For Windows it helps to put the proxytunnel.exe in the same path as putty so that putty can find proxytunnel.exe more easily.

For debugging you can replace the -q option with a -v option and use the command on the command-line. proxytunnel will print what it is doing and where it fails. The above configuration allows you to forward SSH connections to multiple destinations (without the requirement to have SSH running on another port than 22).

To simplify tunneling over SSH, you might want to create a 'dynamic' tunnel using the -D 1080 OpenSSH option. This allows you to socksify any TCP connection and direct it over the SSH tunnel dynamicly.

Most browers allow to socksify their own stack by simplying configuring a socks proxy. In this case you should point your browser to localhost:1080 to surf using the SSH tunnel. proxytunnel has support for SSL tunneling by using the -e option. Unfortunately we discovered a bug in Apache that causes CONNECT (mod_proxy) to fail when SSL is being enabled. You can find more information in Apache's bugzilla at: You can send problems or improvement requests to the proxytunnel mailinglist at: I'm interested in the following improvements to this scheme: