Internet mail trouble

I have trouble getting mail with the Internet to work, despite trying many 
settings as found in Admin Help and several books. I believe the setup is 
quite common and simple.

The setup:
Domino 5.0.9 running on Linux 2.4
Domino server is named server1/myorg. There is only one Domino server in 
this scenario.
Domino domain is mydomain.
OS FQDN is box1.mmmi.com, IP is 192.168.0.200 (a private net). mmmi.com is 
not registered nor visible to the Internet.
The users are all connected to box1 on a tcpip lan and everything but 
external mail is working fine.
box1 has a dialup connection to an ISP for browsing and mail. The connection 
to the ISP is dial-on-demand, so the line comes up whenever there is traffic 
for the Internet, and works fine.
box1 runs DNS which is the master DNS for mmmi.com (ie the LAN computers). 
This DNS uses the ISP nameservers as forwarders (ie if box1's DNS cannot 
provide the requested information, it will forward the request to the ISP's 
nameservers).
The users have Internet pop3 accounts at ourowncompany.com.
Thus, the users each have two (or more) names: a Notes name (eg CN=Bob 
Smith/O=myorg), and an Internet name (eg [email protected]). One 
receptionist has three Internet addresses: her own plus 
[email protected] and [email protected]).
For external mail, fetchmail, running on box1, collects mail from 
ourowncompany.com on a schedule and forwards to port 25, where Domino's SMTP 
task listens.

Fetchmail works fine (though the user account name translation might be set 
incorrectly). Internal mail works fine.

So my question is: What are the correct values (given above names for 
things) in which documents to make this work?

One more question: Where is the nameserver for Domino's SMTP task set? There 
must be a way to tell the SMTP task which nameserver to use.


Sincerely,
Aleksander

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