Restrict ETRN command upon...
smtpd_etrn_restrictions
This parameter restricts what clients are allowed to issue the ETRN
command. The present Postfix ETRN differs from other ETRN
implementations in that it flushes mail for all destinations. This will change
in the future.
The default is to allow ETRN from any host. The following restrictions
are available:
- reject_unknown_client: reject the request if the client hostname
is unknown.
- permit_mynetworks: permit if the client address matches $mynetworks.
- check_client_access maptype:mapname: look up client name, parent domains, client address,
or networks obtained by stripping octets. Reject if result is
REJECT or "[45]xx text". Permit otherwise.
- reject_maps_rbl: reject if the client is listed under $maps_rbl_domains.
- reject: reject the request. Place this at the end of a restriction.
- permit: permit the request. Place this at the end of a restriction.