If you are like me, the idea of learning off port numbers is quite daunting, and if you look at a list of them it seems like they are never ending and so similar that they can not be distinguished.
In my study I have broken them into categories and uses which is helping me to recognise them a bit more (I still have a long way to go!)
Web Traffic
| Port | Protocol | Use |
| 80 | HTTP | Unencrypted web browsing |
| 443 | HTTPS | Secure web browsing (SSL/TLS) |
Email Services
| Port | Protocol | Use |
| 25 | SMTP | Sending email (basic) |
| 110 | POP3 | Receiving email (downloadable to device) |
| 143 | IMAP | Receiving email (keeps mail on server) |
| 993 | IMAPS | Secure IMAP |
| 995 | POP3S | Secure POP3 |
File Transfer
| Port | Protocol | Use |
| 20/21 | FTP | File transfer (unsecure) |
| 22 | SFTP | Secure file transfer (via SSH) |
| 69 | TFTP | Lightweight file transfer (no authentication/ encryption) |
Remote Access
| Port | Protocol | Use |
| 22 | SSH | Secure remote access (command line) |
| 23 | Telnet | Unsecure remote access (avoid) |
| 69 | RDP | Remote desktop (Windows GUI Access) |
Network Services
| Port | Protocol | Use |
| 53 | DNS | Domain name resolution |
| 67/68 | DHCP | Assigning IP addresses |
| 161 | SNMP | Network monitoring |
| 123 | NTP | Time sync |
Directory Services
| Port | Protocol | Use |
| 389 | LDAP | Directory lookups (AD) |
| 636 | LDAPS | Secure LDAP (encrypted) |
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Roisin Gleeson