AUTHREQUIRED

Allow sending of messages (for this host and relaying) only to authenticated senders.

Default:

off

Affects:

qmail-smtpd

Example:

"" (any value will do)

Note:

Use this only if all clients support SMTP-AUTH. Be careful not to block remote mail servers sending messages for local users.
This is only useful if you want to restrict certain IP ranges (for example you dial-up or other customers) to be able to send only as existing and valid users.