9.1 Why multihosting?

You want your system/cluster to provide Web service for more than one domain. You could be a VMS-based ISP (e.g., Pageweavers.com in Sacramento, CA), or implementing a server consolidation program, or a hobbyist hosting a personal and a club Web site.

One approach, which is, in my opinion, really ugly, is to assign different sites to different ports on the server. Since people keying in the URL are likely to forget the :8001, they may get presented with the wrong site, and you get a support call. I like this so little that I'm not going to discuss in any detail how to do it.

You can put multiple node names in the Domain Name Server system that all resolve to the same numeric IP address. When modern browsers connect, they remember what alphabetic name they were looking for and tell the server, using the host header. (This is the CNAME, or Canonical Name.) Unfortunately, one of the antique browsers that doesn't support the host header is Netscape 3.03 on VMS; fortunately, as I write, Mozilla has reached a state of sufficient maturity that Compaq is releasing it as the Compaq Secure Web Browser (CSWB). If there's no host header and you haven't configured the server with a default host or an explicit numeric host, results can be surprising.

While you can make the browser issue a redirect to a particular directory tree based on the CNAME, you can also use multihosting configuration to simply serve from...