In this article I will show the steps to troubleshoot Synology Mailplus server
Access via SSH the NAS
turn on SSH at your own risk and login via the following instruction, click here.
Live view with aggr_maillog
see postfix/smtpd messages
cd /volume1/@MailPlus-Server/aggr_log
sudo tail -f aggr_maillog
TCPDUMP
Install diagnosis tool:
sudo synogear tool
cd/var/packages/DiagnosisTool/target/tools
sudo ./tcpdump -i eth0 port 25 -v
Daily report
- warning: postfix-script
not owned by root: /var/spool/@MailPlus-Server/postfix/.
According to Synology Support those warnings can be safely ignored.
SMTP Port Used
Keep the following in mind:
The Synology Mail Plus server uses SMTP port 25 exclusively to negotiate mail transfers with other messaging servers
So open port 25 in firewall rules for this kind of traffic, like with a relay server. Port 587 doesn’t need to open for this kind of traffic.
