Become superuser on the system for which you have changed a configuration file.

Type pkill -HUP /usr/lib/sendmail and press Return.

sendmail is restarted.

Send test messages from each system by typing /usr/lib/sendmail -v names </dev/null and press Return.

Specify a recipient's e-mail address in place of the names variable. This command sends a null message to the specified recipient and displays messages while it runs.

Run the following tests.

• Send mail to yourself or to other people on the local system by addressing the message to a regular user name.

• If your system is on an Ethernet, send mail to someone on another system. Do this in three directions: from the main system to a subsidiary system, from a subsidiary system to the main system, and from a subsidiary system to another subsidiary system.

• If you have a mail gateway, send mail to another domain from the mail host to ensure that the gateway is configured properly.

• If you have set up a UUCP connection on your phone line to another host, send mail to someone at that host and have that individual send mail back or call you when the message is received.

• Ask someone to send you mail over the UUCP connection. The sendmail program cannot tell whether the message gets through because it hands the message to UUCP for delivery.

• Send a message to the postmaster on different systems and make sure that it comes to your postmaster's mailbox.