Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!leah!rpi!pawl!shadow From: shadow@pawl.rpi.edu (Deven T. Corzine) Newsgroups: news.newusers.questions Subject: Re: questions Message-ID: Date: 28 Jul 89 19:45:56 GMT References: <4051@udccvax1.acs.udel.EDU> Sender: usenet@rpi.edu Distribution: usa Organization: Rensselaer Polytechnic Institute, Troy, NY Lines: 37 In-reply-to: mellon@zayante.pa.dec.com's message of 28 Jul 89 03:18:50 GMT On 28 Jul 89 03:18:50 GMT, mellon@zayante.pa.dec.com (Ted Lemon) said: mellon> As you can see, there are two sorts of address operators being mellon> used here - the ! (bang) and @ (at) operators. The @ operator mellon> takes precedence over the ! operator, which means that an mellon> address like ``foo!bar@baz'' tells your mailer to send the mellon> mail to the machine baz, which will send the mail to the mellon> machine foo, which will send the mail to the user bar. Ugh. This is BAD advice. ! and @ were NOT intended to be used together. Up until recently, there was not even a general concensus as to which takes precedence. It has been generally agreed that @ should take precedence over !, but you can't depend on mailers to be consistent with that. Quite a number of mailers will give ! precedence and attempt to deliver mail addressed to "foo!bar@baz" to machine foo for forwarding to user bar at machine baz. Or, you may get an error because the mailer doesn't know machine foo. (but does know machine baz) Depending on consistent interpretation of an address mixing ! and @ is a poor idea at present. It is much safer to use "baz!foo!bar" instead of foo!bar@baz"; there is only a single interpretation. ! and @ together is ambiguous. As far as % handling goes, for those mailers which implement it (which are most mailers) it will do a full delivery from !'s or @ machines, and at its destination, if it contains a %, the LAST % will be changed into an @ by the mailer, and the message will reenter the mail delivery system. The upshot of which: ! and @ both have precedence over %, and "baz!foo!bar" is (usually) equivalent to "bar%foo@baz". Deven -- Deven T. Corzine Internet: deven@rpi.edu, shadow@pawl.rpi.edu Snail: 2214 12th Street, Troy, NY 12180 Phone: (518) 271-0750 Bitnet: deven@rpitsmts, userfxb6@rpitsmts UUCP: uunet!rpi!deven Simple things should be simple and complex things should be possible.