kurt@hi.unm.edu (Kurt Zeilenga) (03/26/88)
What do you do with something like: a!b%c (where a, b, and c could domainized) A lot of mailers on internet appear to do: b%c@a (tack on .UUCP if a isn't domainized) I prefer: a!b@c (deliver to c) because many folks here address things to a!b and I will forward them to d for forwarding to c. So I give d a "a!b%c@d". Now, I could give d "a!b@c@d", but that has two '@', or just "a!b@c". What is considered defacto standard way(s) of rewriting "a!b%c"? What is the defacto standard way of doing relays as described above? -- Kurt (zeilenga@hc.dspo.gov)
ehrlich@blitz (Dan Ehrlich) (03/28/88)
In article <23560@hi.unm.edu> kurt@hi.unm.edu (Kurt Zeilenga) writes:
-...
-What is considered defacto standard way(s) of rewriting "a!b%c"?
-
-What is the defacto standard way of doing relays as described above?
-...
You should get a copy of RFC886, "Proposed Standard for Message Header
Munging". This RFC is dated December 1983 and I have not heard or seen
any updates to it so this should be the latest "proposed standard".
Having read this document a few times it is still not clear how to
answer your question. But my gut feeling is that "a!b%c" should be
rewritten as "a@b" or perhaps "@c:a@b", or maybe even "b@c" .... :-)
Other RFCs that may be of interest are:
RFC822 - Standard for the Format of ARPA Internet Text Messages
RFC974 - Mail Routing and the Domain System
RFC976 - UUCP Mail Interchange Format Standard
--Dan Ehrlich
Dan Ehrlich <ehrlich@psuvax1.{cs.psu.edu,bitnet,uucp}>
The Pennsylvania State University, Department of Computer Science
333 Whitmore Laboratory, University Park, PA 16802
+1 814 863 1142 or +1 814 865 9723rpw3@amdcad.AMD.COM (Rob Warnock) (03/30/88)
>In article <23560@hi.unm.edu> kurt@hi.unm.edu (Kurt Zeilenga) writes: >-What is considered defacto standard way(s) of rewriting "a!b%c"? The "%" is neither a "!" nor a "@", and thus is (or *should* be) left alone by any of the transport/routing programs. It *may* be interpreted by "local" mail delivery systems, and in particular is handled by "sendmail", and many SMTP mailers (although seldom by non-sendmail UUCP mailers). The defacto standard way, and the reason for the "%" at all (as opposed to "@"), is to defer any rewriting unless you are system "a", in which case you have already stripped the "a!", and are trying to deliver mail to a local "user" named "b%c". At this point (and *only* at this point), you notice the "%", and re-write "b%c" as "b@c", and then do whatever you do locally with "@" addresses (including sending it back out again). If you are not "a", you send it via UUCP to "a" (if you know how :-). The purpose of the "%" is to avoid the ambiguity that arises with mixed "!" and "@". By the way, "%" is often used in the SMTP world. The address "b%c@a" means exactly the same as above: If you are system "a", the "b%c" is a "local-part", which you can (but are not required to) re-write to "b@c". So, for example, in SMTP-land you can often send a "mail-echo" be sending to "me%my-system@other-system". p.s. Note that the usual example, "a!b@c", *cannot* be parsed corectly unless you know what kind of transport it came in on. If it came in on SMTP, then "a!b" is the "local-part", and you should send it to "a" via UUCP. If it came in on UUCP, then "b@c" is the "user", and you should send it to "c" with SMTP (or maybe UUCP, depending on your mail system). Such a mixed-mode horror should *never* be generated locally! If you *have* to send to a "domain" via a UUCP first hop, then use full-bang domain addressing: a!c.dom.ain!b Mailers such as "smail" understand this form. Rob Warnock Systems Architecture Consultant UUCP: {amdcad,fortune,sun,attmail}!redwood!rpw3 ATTmail: !rpw3 DDD: (415)572-2607 USPS: 627 26th Ave, San Mateo, CA 94403
ccdan@ucdavis.ucdavis.edu (Dan Dorough) (03/30/88)
In article <23560@hi.unm.edu> kurt@hi.unm.edu (Kurt Zeilenga) writes: > What do you do with something like: > a!b%c (where a, b, and c could domainized) > > I prefer: > a!b@c (deliver to c) > because many folks here address things to a!b and I will forward them > to d for forwarding to c. So I give d a "a!b%c@d". Now, I could give > d "a!b@c@d", but that has two '@', or just "a!b@c". > > What is considered defacto standard way(s) of rewriting "a!b%c"? the '%' hack isn't actually documented anywhere that i know of. for this reason, it could be considered the "least binding token". it's been my experience that it is far better to resolve host!left%right on the '!' and thus send <left%right> to "host" for delivery. the advantage of the % hack is that it allows for mail to pick it's way through systems that will hopefully leave the '%' parts alone until the the very last. if you start giving it higher precedence than '!', the results will be unpredictable. the only time you would resolve on the '%' in an address of left%right is if the '%' is the only recognized routing token left. --dan dorough, systems programmer, ccdan@ucdavis.edu, (916)752-3420