ATTENTION:

Please make sure that you read %%PREFIX%%/doc/PORT_NOTES.
It contains important information about testing and configuring
qmail, and finally replacing sendmail with qmail.

You should also add %%PREFIX%%/man to your MANPATH (see manpath(1)
or login.conf(5)).

You can enable qmail as your default mailer executing:
> %%PREFIX%%/scripts/enable-qmail