List of mostly used default ports on the CentOS servers
Port Number – Name
20 – FTP
21 – FTP
22 – SSH
25 – SMTP/EMAIL
26 – SMTP
43 – WHOIS
53 – BIND/DNS
80 – HTTP / Apache Web server
110 – POP3/EMAIL
143 – IMAP
443 – HTTPS / Apache Web server SSL
465 – SMTP/EMAIL SSL/TLS
873 – RSYNC
993 – IMAP/EMAIL SSL
995 – POP3/EMAIL SSL
2030 – CWP Admin
2031 – CWP Admin SSL
2082 – CWP User Panel
2083 – CWP User Panel SSL
2086 – CWP Admin (same as 2030)
2087 – CWP Admin SSL (same as 2031)
2304 – CWP External API SSL (https, only for api access like whmcs )
3306 – MYSQL
