Dear List Ok, thank you for the replies as they all point out an apparent PTR Problem, let me reply to the list.
According to my knowledge of the DNS rfcs (I did not look it up right now). A Host resource may point to an A record another host resource is already pointing to. A Host resource could also point to multiple A records (DNS round robin). A in-addr.arpa resource can only point to one PTR record. So if an A record should be reachable under multiple hostnames, only one PTR can be set and that PTR should/must match a host Address resource (this is usually what is verified). cable-static-181-130.breitband.ch => A 184.108.40.206 220.127.116.11.in-addr.arpa => PTR cable-static-181-130.breitband.ch This is the 'main' entry, which matches and passes verification. There is an additional host entry with the name 'mail.aerni.com' which points to the same A Address but cannot have an own PTR record without violating the rfcs about DNS. In fact the customer only has troubles with a handful of destinations, most of smtp servers out there do accept his emails without problems. But I must admit, this is not the 'normal' situation. The customer in question uses that 'dynamically assigned' static IP as a backup internet link only when his main connection is down, which is the case at the moment. So he made some quick DNS changes to restore email reception and noticed the problem sending to a couple of destinations. Mit freundlichen Grüssen -Benoît Panizzon- -- I m p r o W a r e A G - Leiter Commerce Kunden ______________________________________________________ Zurlindenstrasse 29 Tel +41 61 826 93 00 CH-4133 Pratteln Fax +41 61 826 93 01 Schweiz Web http://www.imp.ch ______________________________________________________ _______________________________________________ swinog mailing list email@example.com http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog