BTW, there is at least one email server without MX RR but AAAA RR we all know. Just look into the header of this message. Do you see the Return-Path? Yes? Well, you've found the host I mean.
There is no MX RR for mail.imc.org, but it has an A and an AAAA RR: % dig +short mail.imc.org A 192.245.12.227 % dig +short mail.imc.org AAAA 2001:470:1f04:392::2 Unfortunately, it does not have a corespondig/correct reverse-forward-mapping :-( % display_fwrev_mapping mail.imc.org no: mail.imc.org -A-> 192.245.12.227 -PTR-> Balder-227.Proper.COM -A-> 192.245.12.227 no: -AAAA-> 2001:470:1F04:392:0:0:0:2 -PTR-> properopus-pt.tunnel.tserv3.fmt2.ipv6.he.net -AAAA-> NXDOMAIN Now, we can speculate - Is the missing MX RR by intention? - Is the administrator clueless? - Is he lazy? - Is it just a configuration error (mail.imc.org instead of imc.org)? or we could just ask Paul Hoffman :-) Regards, Michael Storz
