Debugging

sendmail has many debug flags, which you set using the d option. Each debug flag has a number and a level, where higher levels mean "print more information." The convention is that you do not need to set levels greater than 9 unless you are debugging that particular piece of code. Table 3-1 shows some examples of debugging flags.

Table 3-1 Sample sendmail Debug Flags

Debugging Flag	Description
-d12	Sets flag 12 to level 1 (default)
-d12.3	Sets flag 12 to level 3
-d3-17	Sets flags 3 through 17 to level 1 (default)
-d3-17.4	Sets flags 3 through 17 to level 4
-d3,17.4	Sets flag 3 to level 1 (default) and flag 17 to level 4

If you have source code, you can refer to the list of debug flags in the code.