This is the log when I choose my external mail server ip:
May 21 17:33:33 pfsense postfix/postscreen[16712]: CONNECT from [127.0.0.1]:7002
May 21 17:33:39 pfsense postfix/postscreen[16712]: PASS OLD [127.0.0.1]:7002
May 21 17:33:39 pfsense postfix/smtpd[30639]: connect from localhost[127.0.0.1]
May 21 17:33:39 pfsense postfix/smtpd[30639]: NOQUEUE: reject: RCPT from localhost[127.0.0.1]: 450 4.7.1 <ABUNASER>: Helo command rejected: Host not found; from=<
anhuda@sesric.org> to=<
networkadmin@sesric.org> proto=ESMTP helo=<ABUNASER>
May 21 17:33:39 pfsense postfix/smtpd[30639]: disconnect from localhost[127.0.0.1]
May 21 17:34:39 pfsense postfix/postscreen[16712]: CONNECT from [127.0.0.1]:58545
May 21 17:34:39 pfsense postfix/postscreen[16712]: PASS OLD [127.0.0.1]:58545
May 21 17:34:39 pfsense postfix/smtpd[30639]: connect from localhost[127.0.0.1]
May 21 17:34:39 pfsense postfix/smtpd[30639]: NOQUEUE: reject: RCPT from localhost[127.0.0.1]: 450 4.7.1 <ABUNASER>: Helo command rejected: Host not found; from=<
anhuda@sesric.org> to=<
networkadmin@sesric.org> proto=ESMTP helo=<ABUNASER>
May 21 17:34:39 pfsense postfix/smtpd[30639]: disconnect from localhost[127.0.0.1]
Even I couldn't send between my networks.
Nahid