| Port | Service |
| 20,21 | FTP (File transfer) |
| 22 | SSH (Remote login secure) |
| 25 | SMTP (Internet mail) |
| 53 | DNS (Host naming) |
| 80 | HTTP (Web) |
| 88 | Kerberos (computer authentication protocol) |
| 110 | POP3 (Client access) |
| 119 | NNTP (Usenet newsgroups) |
| 123 | NTP (Network time) |
| 137-139 | NetBIOS (DOS/Windows naming) |
| 143 | IMAP (Client access) |
| 161,162 | SNMP (Network management) |
| 163,164 | CMIP (Network management) |
| 443 | HTTPS (Web secure) |
| 514 | Syslog (Event logging) |
| 563 | NNTPS (Usenet newsgroups secure) |
| 993/tcp | IMAP4 over SSL, Internet Message Access Protocol |
| 995/tcp | POP3 over SSL, Post Office Protocol |
| 989,990 | FTPS (File transfer secure) |
| 1723 | Virtual private network (VPN) |