The -d20.1 (a.k.a. -d20)
debugging switch causes sendmail to print each
recipient address before it is rewritten by the
canonify rule set 3 and the
parse rule set 0:
--parseaddr(addr)
Here, addr is the recipient address before it is
rewritten and before any aliasing has been performed on it.
The -d20.1 debugging switch also causes
sendmail to print information about problems
that might exist in recipient addresses. If an address contains any
control or whitespace character that is not an
isspace(3) character,
sendmail prints the following message and skips
that address:
parseaddr-->bad address
If an address is empty (that is, if it is composed entirely of an
RFC2822-style comment), sendmail prints the
following and skips that address:
parseaddr-->NULL
After the recipient address has been rewritten by the
canonify rule set 3 and the
parse rule set 0, and if a delivery agent was
successfully selected, sendmail prints the
result using the printaddr( ) routine.