Hi All

I am sure this has been covered before - but i have not been able to find any posts which satisfy what I am trying to acheive.

In a nut shell, I want to be able to host multiple web sites running on multiple servers (not just one server - so virtual web sites are not an option) all behind a single public IP address all coming through on port 80.

So if i had 3 domains ... www.siteA.com, www.siteB.com and www.siteC.com, they would all be listed on the public address of say 100.100.100.100 and all on port 80. The firewall can only have port 80 and 443 open - so I cant just use different ports.

What I am trying to figure out how to do is have the router (or app running on a linux box) examine the Host Header of the web request and route the request through to the appropriate server sitting behind my firewall, ie,

Domain Public Ip Port Internal Ip Port
www.siteA.com 100.100.100.100 80/443 192.168.1.10 80/443
www.siteB.com 100.100.100.100 80/443 192.168.1.20 80/443
www.siteC.com 100.100.100.100 80/443 192.168.1.30 80/443

The only differentiating information is the Host Header of the web request, so the routing would need to be done at the application Layer - not just the IP and Port layer.

Is there any way to actually acheive this on Linux? I know you can purchase devices for lots of $$ to do web routing or Content based routing, but i really dont want to fork out heaps of cash for a very small set up to rout between a few servers - and before anyone suggests that I just use virtual servers on apache - i need to use separate web servers - virtual is not an option.

Any assistance or advice on how to acheive this would be much appreciated.

Thanks in advance

Rod.

there are dozens of ways to do this on linux, main one would be to use an apache front end with mod_proxy to redirect based on the Host header.

Thanks for the advice

I am learning how to set this up now. It looks like it might just do what I want.

Thanks for pointing me in the right direction

Regards

Rod.

no probs. note of course that you could use one of these boxes for the front end function too, no need for dedicated hardware if you don't have it available.

I plan to have a dedicated virtual machine handling the routing. I have a pretty grunty dual core system with lots of ram available to me. This machine will be hosting several virtual machines - a mix of Windows and mainy Linux machines.

Thanks for your help

Cheers

Rod.

Hey where could I find info on installing mod_proxy. I'm looking to have 2 servers behind a firewall also and I have no clue where to start.

If you are installing on an Ubuntu/Kubuntu server...

the proxy modules are already installed when you install apache2, well they were on each installation i did.

the following information is how I got apache2 reverse proxy working on Kubuntu Dapper 6.06

After you have installed apache2 through standard apt-get repositories...

cd /etc/apache2/sites-available

Now, you can either create a new file for each site that you want, or you can add the configuration to the default file. For mine, i just added the configuration into the default file as follows...

sudo nano default

Just under the NameVirtualHost * line, add the following for each internal server that you want to reverse proxy to...

<VirtualHost *>

ServerName www.externalsite1.com

ProxyRequests Off
ProxyPreserveHost On

<Proxy *>
Order deny,allow
Allow from all
</Proxy>

ProxyPass / http://internalsite1.local/
ProxyPassReverse / http://internalsite1.local/

</VirtualHost>

Repeat the above code for each site that is being reverse proxied to, ie, if you have 2 internal web sites which are publically available through an external IP, the ServerName will be the external URL, such as www.ABC.com, and the internal servers will be www.internalabc.com - or whatever you use for your internal web servers.

Next, Enable the html proxy mod...

sudo a2enmod proxy

Then you have to restart apache...

sudo /etc/init.d/apache2 force-reload

Thats it. A gotcha to be careful of, if you are using DNS names such as URLs, then each machine resolving www.abc.com must resolve to the same IP address. If the calling machine resolves www.abc.com to 192.168.10.1, and the apache reverse proxy resolves www.abc.com to 222.123.54.123,, then the proxy will not work. they must all resolve to the same IP Address. (this is usually only a problem if you are editing host files to test machines before making changes). Just something to watch out for.

Hope this helps.

Cheers

Rod.