- Plesk for Linux
Unable to send emails after the CentOS 7 based server reboot .
Firewall rule that allows connection to mail server is present in Plesk.
Firewall rule that allows connection to mail server is missing in iptables:
# iptables -L -n -v | grep mail.example.com
"firewalld" service is removed or disabled.
1. Re-apply firewall rules in Plesk
1.1. Login to Plesk ;
1.2. Navigate to Plesk > Tools & Settings > Firewall > Modify Plesk Firewall rules and press Apply .
2. Set up iptables to restore the settings after reboot
2.1. Login to the server over SSH
2.2. Install "iptables-services" package
# yum install iptables-services
2.3. Enable iptables as system service:
# systemctl enable iptables
2.4. Save the iptables rules:
# service iptables save