You only need a registered domain name if you want to receive mail from the Internet. If you want to set up a test environment on your LAN where you can send and receive mail from your Sendmail server, you will need to set up a DNS server on your LAN. You can use any domain names you want since nothing will go out on the Internet. I recommend 2 Sendmail servers hosting mail for 2 different domains, and at least one workstation who can send/receive mail between the two servers.
ChrisP ------------------------------------------------------------------------------
If somebody helps you, please click the link in the botton left hand corner that says "Mark this post as a helpful/expert post".