Path: utzoo!utgpu!watserv1!watmath!att!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!batcomputer!munnari.oz.au!mundamutti.cs.mu.OZ.AU!kre From: kre@cs.mu.OZ.AU (Robert Elz) Newsgroups: comp.protocols.tcp-ip.domains Subject: Re: Domain names in resource records (was: PTR records ...) Message-ID: Date: 18 Jan 91 07:39:18 GMT References: <1120@nikhefh.nikhef.nl> <20520@yunexus.YorkU.CA> Sender: news@cs.mu.oz.au Lines: 20 davecb@yunexus.YorkU.CA (David Collier-Brown) writes: >I can comment on (3): berzerkley sendmail breaks on MX->MX, without even >a loop. It evaluates the first MX and stops there. Sendmail is NOT broken here ... the RFC is very precise on this point, and its right. This permits A MX B and B MX A to allow mail to be swapped between two hosts. Don't break it. Any mailer that follows chains of MX records is VERY VERY broken. The illegality of CNAMES anywhere but in the LHS of their own CNAME record is also very clear - violating this will do less damage, and will typically be supported, but be aware that things can go wrong, and if they do, its your fault - its you who has violated the rules. Certainly if you have any secondary servers running BIND they're likely to suffer somewhat - BIND likes to bitch noisily when it detects a CNAME that is used someplace else (but for some reason, not in the primary server...) kre