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 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). => A => PTR

This is the 'main' entry, which matches and passes verification.

There is an additional host entry with the name '' 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

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