Hi fellas!

Due to a change at our ISP I had to set up DNS on my NW5 server. It
hosts a simple SMTP Mailer with POP3 mailboxes (Unoverica freeware).

The DNS should only serve this mailer for

a) finding it's own name
b) forwarding all non local mail to the respective MX's
c) telling the SMTP/POP3 daemon that it's serving "mydomain.com".

The domain is registered and set up externally. The external DNS entry

points to a mail-forwarder in a DMZ that delivers the mail to the
internal "endpoint".

None of the local workstations needs/uses this DNS.

The resolv.cfg contains

"domain mydomain.com"
"nameserver ip-adr-of-NW5-server"

hosts still contains

" localhost... etc"
"ip-adr-of-nw5-server nw5.mydomain.com"

DNS setup is:
Primary for internal IPs but with the external "mydomain.com"
Zones conatin only NW5 with NS, MX and A records
forwarding out to DNS of ISPs

Works for a time but then starts doubling

How is the setup to be changed?
Changing to mydomain.lan and making an alias/MX for mydomain.com?

Any hints welcome.