IP Networking

Hey everyone. Ok I have a question..well a few questions actually, but I'll try to have them make sense.

Ok, I work in a data center and we manage people's servers. One client has an apache server. This apache server has 1 single IP address. When I do ifconfig, it's inet address is 1 address.

That being said, he has multiple different, independent sites on the sever. When I do a dig command to each individual site that's hosted by this one sever, I get a different IP. None of the IP's for those sites match the main IP of the server.

With that in mind when I look at the virtual host directives for each individual site, I see the :<VirtualHost *:80>
Meaning that it's listening for any IP. But most of the sites have this "Listen to all" directive.

So with all of that knowledge, my main question is thus. Where are the individual sites's IP's coming from? Again when I do a dig for these sites, they definitely have an IP address, all of them unique as well. But I see no reference to them in the vhost files. The only thing in their vhost files is the 'listen for all addresses" directive


What's interesting is that when I type in the individual site's IP address, I get an apache page that says site is under construction etc.... but when I type in it's domain name, the site loads properly. So if the VirtualHost directive to listen to all IP's is in play, why does the site's IP's not work when typed into a browser?

Thanks everyone in advance!

If the IP's you're getting from "dig" aren't associated with the server running Apache, then HTTP requests sent to that domain aren't routed to the Apache server directly.

So if they are getting to that Apache server, then the IP's from "dig" are probably for a load balancer or some other front-end. As long as the right HTTP headers are presented, specifically with "Host:" headers that match the VHOST definitions, the fact that there's only one IP address doesn't make a difference.