<div>
I understand what you mean, but I'm not sure if it would help. When I do a reversed Ip Check, It will return a different domain each time. So even if I would config one FQDN for outgoing mail, it would not help. And all my domains have to point to the same IP, otherwise the incoming mail would not arrive.
</div>


<div>
Thanks for both explanations. First tip gave me a lot of info, second was part of the solution. We checked the PTR records, and found we needed to reduce the to 1 PTR record in stead of 1 for every domain. We will test that soon (as we have to adjust all MX records for the other domains's) and if it is working, we will do so for all domain's
</div>


<div>
<div class="content wysiwyg-content">
We have several Mailservers in different countries, all have their own domain, imcd.nl, imcd.be, imcd.uk etc. In one location we have an Email Appliance, for incoming and outgoing mail. That's why the A-records of all these domains point to the same external IPaddress. It happens many times, we send mail to companies, who do a reversed IP check, and then it can happen we send from joe@imcd.nl, but the check returns imcd.uk. Is there a way to avoid this?
</div>
</div>


We have several Mailservers in different countries, all have their own domain, imcd.nl, imcd.be, imcd.uk etc. In one location we have an Email Appliance, for incoming and outgoing mail. That's why the A-records of all these domains point to the same external IPaddress. It happens many times, we send mail to companies, who do a reversed IP check, and then it can happen we send from joe@imcd.nl, but the check returns imcd.uk. Is there a way to avoid this?

Reversed IP check

Within Internet message handling services (MHS), a message transfer agent or mail transfer agent (MTA) or mail relay is software that transfers electronic mail messages from one computer to another using a client–server application architecture. A MTA implements both the client (sending) and server (receiving) portions of the Simple Mail Transfer Protocol (SMTP). The terms mail server, mail exchanger, and MX host may also refer to a computer performing the MTA function. The Domain Name System (DNS) associates a mail server to a domain with mail exchanger (MX) resource records containing the domain name of a host providing MTA services.

Email Servers

The Domain Name System (DNS) is a hierarchical, globally distributed system responsible for associating the name of a computer, service or other resource into an IP address for connecting to the Internet or a private network. Most prominently, it translates domain names to the numerical IP addresses needed for the purpose of computer services and devices worldwide.

Transmission Control Protocol/Internet Protocol (TCP/IP) is the set of networking protocols that define end-to-end connectivity specifying how data should be packeted, addressed, transmitted, routed and received at the destination. This functionality is organized into four abstraction layers which are used to sort all related protocols according to the scope of networking involved.