We have a subsidiary company that's attached to our private WAN.

This company hosts their own DNS, using Microsoft & AD. We use Novell
DNS, and for their domain we're configured as a secondary linked to
their primary.

This subsidiary company also hosts their own e-mail, and our GroupWise
servers communicate with their mail system via the WAN.

Recently we've started having issues with DNS replication between our
companies, and the DNS issue also interferes with e-mail delivery.

On our DNS servers we'll start seeing:

error: transfer of 'xxxxxx.com/IN' from xx.xx.xx.xx#53: failed while
receiving responses: (result code text not available)

....and on GWIA we'll start seeing:

Detected error on SMTP Command
Command: xxxxxx.com
Response: 450 MX lookup failure (xxxxxx.com)

The quick fix is to unload & reload NAMED.NLM. We've had to do that
every day this week. Prior to this week, this configuration has run
without a blip for over two years.

QUESTION 1 - What's causing these DNS issues?

QUESTION 2 - is there a way to tell GWIA the MX for that domain
without using DNS?