I have a Postfix Mail Server running on Unix FreeBSD 8.1-RELEASE on i386. The mail system is POP3 mail. It is running behind a Barracuda Firewall. I have 4 branches and the HQ. The HQ and the other bigger branches are connected through a VPN Link from an ISP. The other 3 branches are connected through Fixed Wireless Broadband and they are supplied by another ISP. All emails are configured on Outlook. The HQ and the other branch connected through VPN Link have no problems with sending/receiving emails internally/externally. The three branches that are using Fixed Wireless Broadband are able to send/receive emails internally and receive external emails. But they cannot send external emails. It stays at the outbox and returned with error "Relay Access Denied". Can someone help me on this issue? I am quite new to to Unix and Postfix Mail server and in deep problem.
Most common mistake is that the users do not authenticate before sending. See: https://serversitters.com/how-to-co...il-errors-and-prevent-them-in-the-future.html Look up your logfile for more information in /var/log/mail.log (could be different in FreeBSD, I don't know this) If that does not help, show the client configuration, log entries on the server, and server (postfix master.cf and main.cf) configuration
https://phoenixnap.com/kb/how-to-view-read-linux-log-files Since you posted the same question in the ISPConfig forum: If you use ispc, you can also watch them at ISPC -> Monitor -> Show Mail Log As you don't know anything about administrating a linux server, I assume you have not messed with any files manually and everything is in the condition of the "perfect server" guide? Then the problem is your mail clients. Ensure in your mail clients you have activated sender authentification
Thanks Stein. Nothing on the server has been touched as yet. I just want to understand and go into the main.cf file to see and confirm all settings are ok. I have checked on the mail client on Outlook and all configs are ok. It was working ok since March when I decided to change the ISP.
Some ISP (like the German Telekom) block outgoing SMTP traffic to unknown servers to prevent spam. Usually you can set this in their web interface or search the internet. Most often other people had the same problem before
Thanks. I will revisit the main.cf file which I can also see it as a plain text from web interface. I'm still baby to the codes that is where the issue is.
