Name
-d8.2
Synopsis
The routine dns_getcanonname( ) in
domain.c of the sendmail
source converts a hostname to a fully qualified domain name. This
routine is called only if DNS is used to look up hostnames, as
determined by the ResolverOptions
option (ResolverOptions) and the ServiceSwitchFile
option (ServiceSwitchFile). If it is,
dns_getcanonname( ) can be called from three
places: during startup to get the values for $w
,
$j
, and $m
(-d0.4); when a host is looked up via the
$[
and $]
canonify operators
(Section 18.7.6); or when a host is looked up using the
host
database map (host).
The -d8.2
debugging switch shows the hostname
before it is fully qualified with this call:
dns_getcanonname(host, flag)
If the flag is nonzero, calls to the getmxrr( ) routine (which looks up MX records) are also traced. On entry to that routine, sendmail will print:
getmxrr(host, droplocalhost=bool)
The host is the hostname whose MX records are
being looked up. The bool, if nonzero, means
that all MX records that are less preferred than the local host (as
determined by $=w
) will be discarded. If zero,
they will be retained.
The -d8.2
debugging switch also causes
sendmail to show the result of processing the
ResolverOptions
option’s settings
(ResolverOptions) while reading the configuration file:
_res.options = hex, HasWildcardMX = 1 or 0
The hex is a hexadecimal representation of the
state
structure’s
options
variable as described in
<resolv.h>. The value of
HasWildcardMX
is determined by its prefix
(+
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