Well-Known Ports & Protocols

Protocols

The following is a quick summary of well-known ports that everyone can learn!

File Transfer Protocol (FTP)

20 | TCP | Upload, download, and manage/transfer actual files

File Transfer Protocol (FTP)

21 | TCP | Manage client/server sessions for file transfer

Secure File Transfer Protocol (SFTP)

22 | TCP | Upload, download, and manage files securely

Secure Shell (SSH)

22 | TCP | Open secure remote host sessions

Telnet

23 | TCP | Open remote host sessions

Simple Mail Transfer Protocol (SMTP)

25 | TCP | Send mail between mail servers

Domain Name System (DNS)

53 | TCP/UDP | Hostname to IP (google.com to 8.8.8.8)

Dynamic Host Configuration Protocol (DHCP)

67 | UDP | Server listens for requests from new devices for an IP

Dynamic Host Configuration Protocol (DHCP)

68 | UDP | Client sends request to server and receive response on this port

Trivial File Transfer Protocol (TFTP)

69 | UDP | Insecure file transfer

Hyper Text Transfer Protocol (HTTP)

80 | TCP | Insecure download of text, graphics, and multimedia by client from server

Post Office Protocol version 3 (POP3)

110 | TCP | Retrieve mail from server; password in plain text

Network Time Protocol (NTP)

123 | UDP | Syncs time between systems

Internet Message Access Protocol version 4 (IMAP4)

143 | TCP | Retrieve mail from server

Simple Network Management Protocol (SNMP)

161 | UDP | For managing network devices (routers, switch, servers etc) through request from Network Management System (NMS)

Simple Network Management Protocol (SNMP)

162 | UDP | Trap messages = alerts from device to NMS w/o prompting about device status and usage

Lightweight Directory Access Protocol (LDAP)

389 | TCP/UDP | managing user accounts, permissions, and other resources in central location

Hyper Transfer Text Protocol Secure (HTTPS)

443 | TCP | Secure download of text, graphics, and multimedia by client from server

Server Message Block (SMB)

445 | TCP | allows direct access to files, directories, and printers on a remote server as if they were local

Syslog

514 | TCP/UDP | A way for applications and systems to write to a centralized log

Simple Mail Transfer Protocol over Transport Layer Security (SMTP/TLS or SMTPS)

587 | TCP | Send mail securely

Lightweight Directory Access Protocol Security (LDAPS)

636 | TCP/UDP | Securely managing user accounts, permissions, and other resources in central location

Internet Message Access Protocol over Transport Layer Security (IMAP/SSL or IMAP/TLS)

993 | TCP | Retrieve/download mail from server securely

Post Office Protocol version 3 over Transport Layer Security (POP3/SSL or POP3/TLS)

995 | TCP | Retrieve/download mail from server securely

SQL Server

1433 | TCP | Microsoft SQL Server; query databases using structured query language

SQLnet

1521 | TCP | Oracle; query databases using structured query language

MySQL

3306 | TCP | Query databases using structured query language

Remote Desktop Protocol (RDP)

3389 | TCP | Renders the remote desktop session on the client while transmitting keystrokes, mouse movements, and clipboard data

Session Initiation Protocol (SIP)

5060, 5061 | TCP/UDP | VoIP