Multiple web servers behind a single firewall

Question

I have multiple web servers behind a single firewall (SVN, Exchange, etc.). I want to be able to access all of the various servers remotely, but since they are All using the same port (the standard HTTPS), is this possible?

If I set it up so that each is listening on different ports, would it be possible to make it so that I could access each server using a different sub-domain (so svn.domain.com would point to svn, mail.domain.com would point to exchange server)? Is there perhaps a way to set up my router to forward a port differently depending on which sub-domain the client requested?

How do people normally go about this issue?

Answer 1

Personally I like using a reverse proxy in apache when serving multiple servers behind one IP address. I wrote up an article on this a few years ago.

There may be times when you need to have multiple web servers, but you have been given only one Public IP Address. The issue you will run into is that you want to have your multiple domains resolve the same IP address, but point to a different server. This is very doable with Apache. I configured a gateway server within my private cloud with an address of 192.168.1.2. I have several web servers with local addresses; 192.168.1.10 and 192.168.1.11 for example.

On my Gateway server, I install Apache and the mod_proxy files. Once this is complete, I am able to set up the virtual hosts to forward the domain.

<VirtualHost *:80>
   DocumentRoot /var/www/example.org
    ServerName *.example.org
    ProxyRequests Off
    <Proxy *>
      Order deny,allow
      Allow from all
    </Proxy>
    ProxyPreserveHost on
    ProxyPass / http://192.168.1.10/
    ProxyPassReverse / http://192.168.1.10
</VirtualHost>

<VirtualHost *:80>
   DocumentRoot /var/www/example.com
    ServerName *.example.com
    ProxyRequests Off
    <Proxy *>
      Order deny,allow
      Allow from all
    </Proxy>
    ProxyPreserveHost on
    ProxyPass / http://192.168.1.11/
    ProxyPassReverse / http://192.168.1.11/
</VirtualHost>

Restart Apache and configure your router to accept incoming connections to the 192.168.1.2 local address. Though I could have pointed the DocumentRoot to the same location (i.e. /var/www), but I usually have .htaccess files for each site where I can force SSL (redirect 80 to 443 on specific domain names).

The nice thing about this route is that you can serve multiple HTTPS servers with the same IP Address. The only issue is that Internet Explorer doesn't recognize the VirtualHost port 443 or named host and you would get a certificate error. However, Safari, Firefox and Chrome all recognize each individual certificate for the domain that is being proxied.

Answer 2

Kobaltz's is probably the best solution.

But if you are willing to use a non-default ports you can setup port forwarding (actually its just NAT that changes the source/destination port) of one of the apps. So you would have one of them represented as normal port 443 for https and the other at something like 8443. To browse to that other server you will need to enter https://youipaddress:8443 (or the DNS entry if you have one setup). Of course this only works if you are willing to use a different port number, but its a pretty common solution when capabilities are limited.

Specific configuration will vary greatly based on the edge device performing the NAT (your firewall or router), but generally you will translate like this:

internal IP -> External IP (possible the IP of your outside interface) standard port (443) -> selected port (eg. 8443)

Here is a good article on port-forwarding.

Answer 3

Or you can use PageKite :)

See project page below:
https://pagekite.net/wiki/OpenSource/

Answer 4

You can accomplish this by setting up subdomains in your internal and external DNS. Here is a good article explaining what you need to add based on what DNS your are running. Remember, when adding entries to external DNS, it takes time to propagate.

Answer 5

Here's the Microsoft documentation to set up a proxy server.