How to test sendmail?

To test to see if your sendmail is working, type in either of the following lines:

 telnet yourdomain 25
telnet localhost 25
telnet 127.0.0.1 25

Then once you are in the telnet, type:

 HELO yourdomain
MAIL FROM: user1@domain1
RCPT TO: user2@domain2

Now type in

 DATA

You should get a response back such as:

 354 Enter mail, end with "." on a line by itself

Type in something and end everything with a dot on the last line, then hit enter. Then check your email for new messages.