Internet Message Access Protocol (IMAP4)
Port 143 - protocol designed to download email but allows a user to stay connected so new emails appear automatically, unlike POP3. Also, allows emails to remain server side and doesn’t force you to download them like POP3
Simple Network Management Protocol (SNMP)
Port 161/162 - gathers and manages network performance by using an SNMP server and collecting data from devices (Called agents) to ensure the network is operating properly
Lightweight Directory Access Protocol (LDAP)
Port 389 - designed to access information stored in information directory’s (Think Active Directory) known as an LDAP directory or LDAP Database. Based on the X.500 standard
Hypertext Transfer Protocol Secure (HTTPS)
Port 443 - connection based protocol that allows access to websites via an encrypted path using SSL or TSL
Remote Desktop Protocol (RDP)
Port 3389 - allows users to connect to remote computers and run programs on them
Server Message Block (SMB)/ Common Internet File System (CFIS)
Port 445 - used to provide shared access to files, printers, and other network resources and is primarily implemented by Microsoft systems
Network Basic Input/Output System (NetBIOS)/NetBIOS over TCP/IP (NetBT)
Port 137-139 - An application programming interface (API) that allows computers to communicate with each other over the network. Provides three services - Naming service, Datagram distribution service, Session management service
Post Office Protocol 3 (POP3)
Port 110 - protocol for downloading email from a server. It has been largely replaced by IMAP4
Dynamic Host Configuration Protocol (DHCP)
Port 67-68 - Dynamically assigns IP addresses and other IP configuration information to network clients
Hypertext Transfer Protocol (HTTP)
Port 80 - Less secure version of HTTPS, which allows access to websites
Domain Name Service (DNS)
Port 53 - Resolves hostnames to IP addresses
Simple Mail Transfer Protocol (SMTP)
Port 25 - Used to send email messages
Telnet
Port 23 - Unsecure version of SSH, allows remote connection to machines in plain text
Secure Shell (SSH)
Port 22 - Secure remote connection to machines, replaced Telnet
File Transfer Protocol (FTP)
Port 20/21 - Used to transfer files; an application and an protocol
