When combined with -d, causes some otherwise lost debugging information to be printed.
Holds the sendmail daemon in the foreground so that -d debugging information about the running daemon can be viewed.
Shows the general configuration of your system: -d0.1 prints version information (§37.5.1); -d0.4 prints the local hostname and any aliases found for it (§37.5.2); -d0.15 prints a list of the delivery agents declared (§37.5.4); and -d0.20 prints the address of each network interface found (§37.5.5).
Traces most DNS lookups: -d8.1 prints failure of the low-level MX search (§37.5.30); -d8.2 prints calls to getcanonname(3) (§37.5.31); -d8.3 traces dropped local hostnames (§37.5.32); -d8.5 shows hostnames being tried in getcanonname(3) (§37.5.33); and -d8.8 shows when MX lookups get the wrong type (§37.5.35).
Traces delivery agent calls: -d11.1 traces arguments passed to the delivery agent (§37.5.44); and -d11.2 prints the user ID that the delivery agent is being invoked as (§37.5.45).
Traces rewriting of addresses: -d21.1 traces general rule set rewriting (§37.5.67); -d21.2 traces use of the $& macro (§37.5.68); -d21.3 shows $> subroutines being called (§37.5.69); -d21.4 displays the result of rewriting (§37.5.70); -d21.15 shows $digit replacement (§37.5.73); and -d21.35 shows token-by-token LHS matching (§37.5.74).
-d27.1 traces general aliasing
:include: files, alias self-references,
and errors on home
-d27.3 traces trying the ~/.forward path and
the alias wait
-d27.4 prints "not safe" when a file is unsafe to trust
and -d27.9 shows uid/gid changes that
:include: file reads
Traces macros: -d35.9 shows macro values being defined (§37.5.120); -d35.14 shows macro names being converted to integer identifiers (§37.5.121); and -d35.24 shows macro expansion (§37.5.122).
Traces options and class macros: -d37.1 traces the setting of options (§37.5.126); and -d37.8 traces the adding of words to a class (§37.5.127).
Traces the queue: -d41.1 traces queue ordering (§37.5.144); -d41.2 shows failure to open qf files (37.5.145); -d41.49 shows excluded (skipped) queue files (§37.5.146); and -d41.50 shows every file in the queue (§37.5.147).
check_ rule sets:
-d48.2 traces calls to the
check_ rule sets