Debugging sendmail
There is a fairly large number of debug flags
built into
sendmail.
Each debug flag has a number and a level,
where higher levels cause more information to be printed out.
The convention is that levels greater than nine are not required.
They print out so much information that you would not normally
want to see them, except for debugging that particular piece of code.
Debug flags are set using the sendmail -d
command-line flag. The syntax is: