In Mac OS X Server v10.6, Postfix is configured to require a fully qualified hostname from SMTP clients. This setting is configurable and the restriction can be removed however any modification of a security-related setting should be evaluated prior to making the change.
Once you have evaluated the change you can use the following steps to implement it:
Note: Before proceeding back up the /etc/postfix/main.cf file as a precaution.
- In /etc/postfix/main.cf locate the smtp_client_restrictions setting
- Remove “reject_non_fqdn_hostname” from the list of settings.
- Restart the Mail service.
- Carefully edit /etc/postfix/main.cf (using terminal or a proper text editor) and change:
- smtpd_helo_restrictions = reject_invalid_helo_hostname reject_non_fqdn_helo_hostname
- smtpd_helo_restrictions = permit_sasl_authenticated permit_mynetworks reject_invalid_helo_hostname reject_non_fqdn_helo_hostname