While this covers several aspects of setting this up on most platforms, there are always exceptions to rules which may complicate the process. I will attempt to address all pertinent issues. The current version of Sendmail from Berkeley is 8.8.8. This version has security enhancments for all known sendmail bugs. Before installing and configuring the daemon, you need to determine what function you would like the sendmail process to perform.
Most people choose to have their sendmail client act as a nullclient.
If you choose to have a fullclient, you can choose to have your return address include your host's fully qualified domain name. If you want to run a fullclient you must verify that your host has an MX record of 0. This can be accomplished by using nslookup. Type nslookup on your Unix machine. This machine does NOT have an MX record pointing to itself.