The 'standard' ports for services you may wish to open in your firewall are...
- FTP | Port 21
- SSH | Port 22
- TELNET | Port 23
- SMTP | Port 25
- WEB | Port 80
- POP3 | Port 110
- IMAP | Port 143
- HTTPS | Port 443
- MySQL | Port 3306
- DNS | Port 53
- DHCP | Port 58
- TFTP | Port 69
- SNMP | Port 161
- LDAP | Port 389
- RSync | Port 873