chkuser will check for recipients only if it is requested to do so.
With standard settings, chkuser check recipients if recipient's domain
has bouncing enabled.
Standard bouncing may be set for each domain using qmailadmin, or
manually using a .qmail-default like this one:
| /vpopmail/bin/vdelivermail '' bounce-no-mailbox
If you have a not standard installation, or checking must be done with
different criterias,
see the
settings page for the additional #define available, or
look inside
FAQs for more explanations.
