Path: utzoo!attcan!uunet!husc6!uwvax!rutgers!columbia!cunixc!alan From: alan@cunixc.columbia.edu (Alan Crosswell) Newsgroups: comp.protocols.tcp-ip Subject: Re: Domain name/subnet relationship. Message-ID: <747@cunixc.columbia.edu> Date: 27 Jun 88 12:47:37 GMT References: <8806270548.AA23542@ucbvax.Berkeley.EDU> Reply-To: alan@cunixc.columbia.edu (Alan Crosswell) Organization: Columbia University Lines: 28 In article <8806270548.AA23542@ucbvax.Berkeley.EDU> RACKLEY@MSSTATE.BITNET (Mike Rackley) writes: >I am confused about the relationship of domains and subnets. Is there, >or should there be, any specific relationship between domains and subnets? >In particuar, is it possible to have a single domain that contains more than >one subnet? Conversely, is it possible to have a single subnet that contains >more than one domain? Can you have a single domain that is spread among >several subnets? The situation I am wondering about is where a department is >spread among several buildings on campus. Domains are basically a *user* convenience for naming an IP address. There is no required relationship between a domain name and an IP address, network, subnet, campus, etc. In usual practice they happen to correspond since single departments tend to be on a single subnet. However, it is perfectly reasonable to have members of the same subdomain be located on radically different networks (e.g. on opposite sides of the world). You just better hope that a domain name server for that domain is reachable from both those networks (not necessarily the same one!). A lot of people get domains and networks locked together in their minds mainly as a result of poor examples of domain usage like .BITNET and .UUCP where the domain is actually being used to indicate a specific non-IP network. Work is progressing in both these networks to convert to proper domain names. There are now many "MX" servers on the Internet that respond to domain lookups for BITNET and UUCP hosts. Alan Crosswell Columbia University