How do web hosting companies do it?

Simon Waters Simon at wretched.demon.co.uk
Wed Mar 20 00:44:00 UTC 2002


Tom wrote:
> 
> Is it common practice for a web hosting company to assign multiple domain
> names to one IP address and then alias them once the connection is made to
> the machine?

Well not sure what you mean by alias, but yes most shared
servers let the HTTP protocol worry about the domain name of the
request, DNS just makes sure it is the right server.

> Or, does every domain name a hosting company hosts required to have there
> own IP address.

No, some did it this way in the old days, but IP addresses are
scarcer, and all common web browser send the URL with the
request.
 
> The reason I ask is because I can almost never do a reverse lookup, only a
> forward lookup on many domain names.

You 'reverse look up IP addresses', not domain name (Well
technically you convert IP addresses 1.2.3.4 to domain names in
the format 4.3.2.1.in-addr.arpa.).

Simply because multiple domains are parked at one IP address,
doesn't forgive the hoster not having bothered to have put an
entry for the IP address in the reverse DNS, but don't be
surprised if the reverse lookup is a wen hosting server names
"webserver.anotherhostingcompany.net", rather than the domain
name you started with "www.domainIwasexpecting.com".


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