wcs) (02/08/90)
In article <486.25c70abd@uoft02.utoledo.edu> cscon113@uoft02.utoledo.edu (squid) writes: > I will try to mail something to someone, and my mailer will say that there > is a problem in my address. Is there a way to find out the actual numbers > for an address, instead of relying on names? I was trying to reach the > eclipse-request@beach.cis.ufl.edu to get on the mailing list, but my mailer > won't go there. Any help? You probably have a guru at your site who is good at mailers. You can often find this person by sending mail to "postmaster", or maybe "root" on your machine, or walking over to wherever UToledo keeps computer administrators. They can be very helpful about such things. (Unless, of course, that person is YOU, in which case you need some real references to start. Read all the manuals you can find, and get O'Reilly & Associates' Nutshell Handbook on Managing UUCP and USENET. Read comp.unix-wizards and comp.mail.* and anything else relevant.) "Actual Numbers" assumes everything is on one single relatively homogenous kind of network. It's not. There's "The Internet", which is a very large internetwork of machines that all run TCP/IP protocols, which is probably the "actual numbers" you're talking about, but email is a much bigger and stranger game than that. Some networks, like BITnet and DEC's internal mail system, have similar capabilities, but different syntax, addressing/naming, and perhaps radically different internal mechanisms. DEC's stuff runs on VMS, and BITnet runs on IBM mainframes, using operating systems and data communications protocols too evil to name in polite company :-). Traditional UNIX mailers don't use "login@machine.domain", where some magical name-resolver system figures out how to get to the destination and then TCP's it in one fell swoop, they use a store-and-forward scheme where YOU tell the mailer what machines to send it to, and each machine passes it on to the next one. So a mail path looks like: mail machineA!b-vax!3B20-c!uunet!machine-Z!login This means YOU have to know what path to use, but if you DO know the path and all the machines on it are working today, it works very well, without particularly needing any central adminstrative organization to run it. And it can handle all kinds of mailer syntaxes for addresses, as long as the local machine can do the first step. Needless to say, this is too tough for regular users to use conveniently, so most big organizations will have a gateway machine that talks to "all" the machines in the company. This is still tough, so "smart mailers" were developed, which have a table of mail paths to interesting places, and know how to usually get the mail to the destination without a long full path. Of course, if you have one, and it talks to lots of people, lots of people will forward their mail through you. AT&T Bell Labs used to have a machine named "ihnp4" which became the center of the earth; that job has mostly been replaced by "uunet", which charges money for providing such good service. > The one and only SQUID!!! > <Pink Floyd Quote> Careful with that Axe, You Squid! By the way, there ARE other SQUIDs out there, and at least one Squid-Killer. Bill -- # Bill Stewart AT&T Bell Labs 4M312 Holmdel NJ 201-949-0705 erebus.att.com!wcs # ho95c has gone the way of all VAX/785s, so I'm now on erebus.att.com