==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release):
- Deployed with iRedMail Easy or the downloadable installer?
- Linux/BSD distribution name and version:
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
- Web server (Apache or Nginx):
- Manage mail accounts with iRedAdmin-Pro?
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====
iRedMail    v1.1
installer
centos7
MySQL
Nginx

entered the netstat -nt command and saw a lot of entries
tcp 0 0 192.168.168.5:25 208.155.31.10:13725 SYN_RECV

how to protect the server? the server is behind an ordinary router