Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bionet!agate!helios.ee.lbl.gov!ncis.tis.llnl.gov!MIRSA.INRIA.FR!Christian.Huitema From: Christian.Huitema@MIRSA.INRIA.FR (Christian Huitema) Newsgroups: comp.protocols.iso.x400.gateway Subject: Re: an apology to Steve, and more discussion ... Message-ID: <8907201540.AA20284@jerry.inria.fr> Date: 20 Jul 89 15:40:47 GMT References: Sender: root@ncis.tis.llnl.gov Distribution: inet Organization: The Internet Lines: 26 Approved: post-x400-gateway@tis.llnl.gov There is certainly one inconveniency in all those routing tables: if they are not small and stable, e.g. with half a dozen entries per countries, then they wont be up to date, and we must guarantee either an ubiquitous way of accessing them or a default solution. The ubiquitous way is indeed the DNS, through the creation of a new type of field (X400 ?): when queried with a domain name, it would respond with the equivalent X.400 domain. The default solution can also be based on the domain name. Print the orname component as a domain name (OU.O.P.A.C), apply the well known stable mappings in order to reduce to some (OU.O.Top) or (OU.O.P.Top) and then look for the appropiate gateway in the MX records. Or for a CNAME record. It may work. Resulting requirement: if a acquires an X.400 subscription, it has to enter a new record in the DNS, and an MX record for the X400 domain. For example, if IBM.COM gets a subscription from MCI-MAIL, it will have to provide: MX: IBM.COM => IBM gateway; IBM.MCI-MAIL.US => the same IBM gateway; X400: IBM.COM => IBM.MCI-MAIL.US There is no much cost for the existing domains, except indeed for the dreadful ".US" domain which will have to cope with the recording of ADMDs... Christian Huitema