I had many problems when installing sendmail in AIX 4.3.3 when I migrated to 5.1L it worked fine. I add a few lines in the sendmail.cf file and it worked. I was connecting to a MS Exchange server running SMTP.
Here's what was added in /etc/mail/sendmail.cf
DS changed to DSSMTP exchange_server_name
DM changed to DMcompany.name.com
To test the connection you should be able to login to the SMTP exchange server from unix command line:
telnet xxx.xxx.xxx.xxx 25 --->25 is the port number
Trying ...
Connected to xxx.xxx.xxx.xxx
Escape character is '^]
If you see this then your connection is fine and you should be able to sendmail to this server.
Here's what was added in /etc/mail/sendmail.cf
DS changed to DSSMTP exchange_server_name
DM changed to DMcompany.name.com
To test the connection you should be able to login to the SMTP exchange server from unix command line:
telnet xxx.xxx.xxx.xxx 25 --->25 is the port number
Trying ...
Connected to xxx.xxx.xxx.xxx
Escape character is '^]
If you see this then your connection is fine and you should be able to sendmail to this server.