A list of ports required to be completely closed or restricted to only certain hosts:
Windows:
135 - Microsoft RPC
137 - 139 - Windows NetBIOS
161 - 162 - SNMP
445 - File Sharing
1433 - 1434 - Microsoft SQL Server 3389 - Microsoft RDP
Linux:
21 - FTP
22 - SSH
23 - Telnet
25 - SMTP
110 - POP3
161 - 162 - SNMP