If you want separate sites you will have to set them on different ports so they are separated, the DNS lookup is based upon ip address and port. How would you have gone about separating the dns entries for the two sites on one IP and port?

navidnmc wrote:

You can use feature of ( Host Header Name ) in microsoft ISA server for publish muti internal web site with one public ip on default www port 80 .

How i can this publishing in squid ?

That functionality is foreign to me since I prefer not to use any ms products unless I have no other choices. It just doesn't sound right using a proxy to publish websites since the websites are served through a webserver not the proxy server, now if you mean that you are using the caching capability of a proxy server to serve the cached sites then your resolution would be within your internal routing and network setup more than the software.