> >How about these two? > > > >> nullmx.domainmanager.com > >Non-authoritative answer: > >Name: mta.dewile.net > >Address: 69.59.189.80 > >Aliases: nullmx.domainmanager.com > > > >> smtp.secureserver.net > >Non-authoritative answer: > >Name: smtp.where.secureserver.net > >Address: 208.109.80.149 > >Aliases: smtp.secureserver.net > > > >There are two reasons it does not blow up in peoples face. 1) If it is in > >the CNAME RR points to an A record in the same zone, both the A record and > >the CNAME record are returned, thus meeting the A record requirement. 2) > >SMTP servers are required to accept an alias and look it up. Thus there is > >no need for this. > > > >And no it does not matter if there are multiple MX records with different > >preferences values. > > You say, "both the A record and the CNAME record are returned." > We know that BIND does this.
No, not all BIND versions do this. I'm running BIND 9.5, and when asking about the MX for nullmx.domainmanager.com I'm getting Answer: nullmx.domainmanager.com. CNAME mta.dewile.net. Authority: dewile.net. SOA ... Even if my BIND 9.5 name server has the A record for mta.dewile.net in the cache, it is not returned. > Is this part of the RFC? Do other DNS implementation return both > the "A" and the CNAME? My ISP's Nominum CNS name server does the same - returns the CNAME in the answer section, and the SOA for dewile.net in the authority section. No A record for dewile.net is returned. However, this whole debate is rather pointless. We clearly have one person who doesn't want to be convinced. That's okay - but he can't expect ISC (and Nominum, etc) to change their software just because he has a different interpretation of the RFCs than the rest of the DNS world. Steinar Haug, Nethelp consulting, sth...@nethelp.no _______________________________________________ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
