Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cmcl2!rna!amms4!news From: news@amms4.UUCP (news administration) Newsgroups: comp.mail.sendmail Subject: Re: Short-circuiting a route Keywords: sendmail, smail, domain names Message-ID: <438@amms4.UUCP> Date: 5 Jul 89 20:33:16 GMT References: <1047@aber-cs.UUCP> Reply-To: news@amms4.UUCP (news administration) Organization: Eagle Clothes, Inc., New York, NY Lines: 55 In article <1047@aber-cs.UUCP> pcg@cs.aber.ac.uk (Piercarlo Grandi) writes: >In article lear@NET.BIO.NET (Eliot Lear) writes: > > > Domainization is only a scheme to generate reliably unique names, not > > to give routing hints; these should be based on maps. And you should > > never try to second guess somebody's else's maps... > > I'm not sure who is missing the point... > > If a name is unique, then one should be able to short circuit to it, > >And generate interesting mail loops... Again, names may be relative or >absolute, and routing may be source or dynamic, but the two issues are >TOTALLY unrelated. Relative names (a la UUCP net) may LOOK like routes, but >they need not be; conversely absolute names don't imply anything about >routing. Ok - here's my $.02 worth. It seems to me that the UUCP maps, when viewed from 'above', constitute a network (a la graph theory), and the Domain name system is a tree. A string of connected nodes in a network constitutes a path from one to the other. A string of nodes in a tree simply constitutes a unique name for that leaf node. The domain name tree says absolutely NOTHING about which machines talk to which other machines. It just says that a message destined for a machine with the name A.B.C.D can be delivered if it can be given to a machine that knows all of the .C. nodes that hang off of the .D qualifier. It seems to me that trying to short-circuit a !path is a bad thing, unless there is a way to guarantee that all the names in the path are unique. Why? Well, since there is no _guarantee_ that all names in the maps are unique, you just might pick _different_ machine foo than the one targeted by the specified path. Also, _your_ list of just who talks to whom could very easily be older than the connectivity data used by the originator of the message. The path A!B!C!D!E just might be the only way from A to E now that B and E no longer talk to each other. If every name in the maps was a fully qualified domain name, there would be no problem. The machine foo.bar.com would be totally different from the machine foo.bar.edu or foo.bar.mil, etc. Unfortunately, not all sites have FQDN's (including me :-). If the day ever arrives when this state of affairs does exist, then short-circuiting !paths would be ok - on the other hand, it would no longer be necessary :-). Anyway, that's how I see it - any comments? -- Harry | reserved for | something really Internet: hjg@amms4.UUCP (we're working on registering)| clever - any UUCP: {jyacc, qtny, rna, bklyncis}!amms4!hjg | suggestions?