Can you give me some advise: where to look, what to look fore?
These problems started after upgrading from NW 5.1 to NW 6.5, on a
firewall-server where we were running BM 3.8.

Today we have BM 3.8 sp 2, NW6.5 sp2 on our "DMZ-server", there is 3 NIC
(for Public, DMZ and Private.)
On DMZ we have a Notes SMTP server.
Mails is recieved from public throu the DMZ-server to the SMTP-server. It
then sends the recieved mails throu the DMZ-server to a Notes server on the
Private network. When we send mails it goes the opposite happens.

The Problem:
Occasionaly once or twice a week, when handling big mails, it seems as if
there is a break in the communication between the 2 Notesservers. After this
event mailrouting is extreeme slow and more and more mails is not routed.
This can (according to Notes), be solved by restarting the mailrouter.
However this is not enough, this does not solve the problem allone. We have
to restart the DMZ-server before restarting the mail queue.

Any suggestions regarding specific logs on the DMZ-server, TID's, ...
anything will be very much appreciated.