Restrictions on sender addresses
smtpd_sender_restrictions
This parameter specifies optional restrictions on sender addresses that SMTP
clients can send in MAIL FROM commands.
The default is to permit any sender address. The following
restrictions are available:
- permit_mynetworks: permit if the client address matches
$mynetworks.
- reject_unknown_client: reject the request if the client hostname is unknown.
- reject_maps_rbl: reject if the client is listed under
$maps_rbl_domains.
- reject_invalid_hostname: reject HELO hostname with bad syntax.
- reject_unknown_hostname: reject HELO hostname without DNS A or MX record.
- reject_unknown_sender_domain: reject sender domain without A or MX record.
- check_sender_access maptype:mapname: look up sender address, parent domain, or localpart@.
Reject if result is REJECT or "[45]xx text"
Permit otherwise.
- check_client_access maptype:mapname: see
smtpd_client_restrictions.
- check_helo_access maptype:mapname: see
smtpd_helo_restrictions.
- reject_non_fqdn_hostname: reject HELO hostname that is not in FQDN form
- reject_non_fqdn_sender: reject sender address that is not in FQDN form
- reject: reject the request. Place this at the end of a restriction.
- permit: permit the request. Place this at the end of a restriction.
Restrictions are applied in the order as specified; the first
restriction that matches wins.
Specify a list of restrictions, separated by commas and/or whitespace.
Continue long lines by starting the next line with whitespace.