-bH command-line switch causes
sendmail to clear (purge) all the persistent
host-status information that was being saved as a result of the
HostStatusDirectory option (HostStatusDirectory). Note that the
HostStatusDirectory directory is not itself
removed, but all the subdirectories under it are. The
purgestat(1) (Section 15.1.4)
command-line command is a synonym for this switch.
Note that, beginning with V8.10, sendmail only
purges host-status files that exceed the timeout set by the
Timeout.hoststatus option (See this section).