Debug flags for sendmail
There are a large number of debug flags built into the sendmail command.
Each debug flag has a number and level, where higher levels print more information. The convention is levels greater than nine print out so much information that they are used only for debugging a particular piece of code. Debug flags are set using the -d flag as shown in the following example:
debug-flag: -d debug-list
debug-list: debug-flag[.debug-flag]*
debug-flag: debug-range[.debug-level]
debug-range: integer|integer-integer
debug-level: integer-d12 Set flag 12 to level 1
-d12.3 Set flag 12 to level 3
-d3-17 Set flags 3 through 17 to level 1
-d3-17.4 Set flags 3 through 17 to level 4The available debug flags are:
| Item | Description |
|---|---|
| -d0 | General debugging. |
| -d1 | Show send information. |
| -d2 | End with finis( ). |
| -d3 | Print the load average. |
| -d4 | Enough disk space. |
| -d5 | Show events. |
| -d6 | Show failed mail. |
| -d7 | The queue file name. |
| -d8 | DNS name resolution. |
| -d9 | Trace RFC1413 queries. |
| -d9.1 | Make host name canonical. |
| -d10 | Show recipient delivery. |
| -d11 | Trace delivery. |
| -d12 | Show mapping of relative host. |
| -d13 | Show delivery. |
| -d14 | Show header field commas. |
| -d15 | Show network get request activity. |
| -d16 | Outgoing connections. |
| -d17 | List MX hosts. |
Note: There are now almost 200 defined debug flags in sendmail.