Troubleshooting with mailx -v (Sendmail and Mail)

On a number of occasions, I have used mailx -v to trouble shoot problems with Mail and Sendmail. Here's what I do.

#mailx -v supportATtopbloglists.com (hit enter)
Subject: Top Blog Lists (hit enter)
Top Blog Lists has hit 100 members in less than 3 weeks. Join other successful bloggers at http://www.topbloglists.com (hit enter)
. (hit enter)
EOT

--Watch the output scroll--

mailx coupled with -v are very useful because they provide the verbose output of Sendmail. It shows the connection, session and disconnect. It's very useful for troubleshooting purposes (e.g. viewing IPs, DNS, mail configurations, version numbers, etc).