Hi Friends, I have configured Postfix mail server on Centos for relaying mails from 5 linux servers (including itself) within the same LAN. The postfix mail server should relay mails from these 5 linux servers for specific domains only. For example hosts 192.168.0.23/24/25/26/27 and the postfix mail server should only be able to receive and send mails from and to example.com,example2.com and example3.com domains only. Below is the configuration of the postfix mail server myhostname = test.example.com myorigin = $mydomain inet_interfaces = all mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain mynetworks_style = subnet mynetworks = 192.168.0.23/32,192.168.0.24/32,192.168.0.25/32,127.0.0.1/32,192.168.0.26/32,192.168.0.27/32 ,relay_domains = $mydestination,example.com,example2.com,example3.com smtpd_recipient_restrictions = reject_unauth_destination,permit_mynetworks,reject The issue I am facing is that whenever things are working fine when I check the things through telnet but when I do testing through command line through "mail" command I am able to send mails to any domain from these 5 servers. bash-2.05$ telnet test.example.com 25 Trying 192.168.0.27... Connected to test. Escape character is '^]'. 220 test.example.com ESMTP Postfix (2.2.5) mail from:ankush.grover at example.com 250 Ok 501 Syntax: RCPT TO: <address> rcpt to:ankush at gmail.com 554 <ankush at gmail.com>: Relay access denied How can I restrict mails even going through "mail" command from these 5 servers to specific domains only. These 5 servers are running some cronjobs and these cronjobs output it mailed through "mail" command. Regards Ankush