Chapter 2.1: Common Ports

FTP (File Transfer Protocol)

-tcp/20 (active mode data) and tcp/21 (control)

-Transfers files between systems

SSH (Secure Shell)

◦tcp/22

-Encrypted communication link

Telnet (Telecommunication Network)

◦tcp/23

-Login to devices remotely

SMTP (Simple Mail Transfer Protocol)

tcp/25

A standard protocol used for sending emails between servers

DNS (Domain Name System)

◦tcp/53

-Converts names to IP addresses

DHCP (Dynamic Host Configuration Protocol)

udp/67 and udp/68

-Automated configuration of IP address, subnet mask and other options

HTTP (Hypertext Transfer Protocol)

-tcp/80

-Communication in the browser

HTTPS (Hypertext Transfer Protocol Secure)

◦tcp/443

POP3 (Post Office Protocol version 3)

◦tcp/110

-Receive emails from an email server

IMAP4 (Internet Message Access Protocol v4)

tcp/143

-Includes management of email inbox from multiple clients

SMB (Server Message Block)

-tcp/445

-Direct SMB communication over TCP without the NetBIOS transport

LDAP (Lightweight Directory Access Protocol)

◦tcp/389
-Store and retrieve information in a network directory

RDP (Remote Desktop Protocol)

-tcp/3389
-Remote Desktop Services on many Windows versions

NetBIOS session

tcp/139 and tcp/137