参考
設定
/etc/postfix/main.cf
smtpd_client_restrictions =
permit_mynetworks,
+ reject_unknown_client,
permit
ログ確認
$ tail -f /var/log/mail.* | grep rejected
Mar 7 09:54:12 mx.srv1 postfix/smtpd[29547]: NOQUEUE: reject: RCPT from unknown[123.50.215.159]: 450 4.7.1 Client host rejected: cannot find your hostname, [123.50.215.159]; from=error_mail@vixii.co to=user1@myserver.hoge.jp proto=SMTP helo=<[123.50.215.159]>
受信を例外的に許可したい場合
/etc/postfix/main.cf
smtpd_client_restrictions =
permit_mynetworks,
+ check_client_access hash:/etc/postfix/access,
+ reject_unknown_client,
permit
- /etc/postfix/access
/etc/postfix/access
## IP Address Rule
22.22.22 OK # 22.22.22.0/24
#200.189.73.2 REJECT
# Domain Rule
myserver.com OK
mydomain.jp OK
# Address Rule
#testaa@examples.com OK
#spam@spam.com REJECT
設定反映
postmap /etc/postfix/access
service postfix restart