Network Ports and Protocols Cheat Sheet

Network communications are governed by a set of rules called protocols. Each protocol is assigned a port to allow applications to communicate. Below is a list of common protocols;

PORT NUMBER	SERVICE NAME	TRANSPORT PROTOCOL	DESCRIPTION
20	FTP-data	TCP, SCTP	File Transfer Protocol data transfer
21	FTP	TCP, UDP, SCTP	File Transfer Protocol command control
22	SSH/SCP/SFTP	TCP, UDP, SCTP	Secure Shell, secure logins, file transfers (scp,sftp), and port forwarding
23	Telnet	TCP	Telnet protocol, for unencrypted text communications
25	SMTP	TCP	Simple Mail Transfer Protocol, used for email routing between mail servers
42	WINS Replication	TCP, UDP	Microsoft Windows Internet Name Service, vulnerable to attacks on a local network
43	WHOIS	TCP, UDP	Whois service, provides domain-level information
49	TACACS	UDP; can also use TCP but not necessarily on port 49	Terminal Access Controller Access-Control System, provides remote authentication and related services for network access
53	DNS	TCP, UDP	Domain Name System name resolver
67	DHCP/BOOTP	UDP	Dynamic Host Configuration Protocol and its predecessor Bootstrap Protocol Server; server port
68	DHCP/BOOTP	UDP	Dynamic Host Configuration Protocol and its predecessor Bootstrap Protocol Server; client port
69	TFTP	UDP	Trivial File Transfer Protocol
80	HTTP	TCP, UDP, SCTP	Hypertext Transfer Protocol (HTTP) uses TCP in versions 1.x and 2. HTTP/3 uses QUIC, a transport protocol on top of UDP
88	Kerberos	TCP, UDP	Network authentication system
102	Microsoft Exchange ISO-TSAP	TCP	Microsoft Exchange ISO Transport Service Access Point (TSAP) Class 0 protocol
110	POP3	TCP	Post Office Protocol, version 3 (POP3)
113	Ident	TCP	Identification Protocol, for identifying the user of a particular TCP connection
123	NTP	UDP	Network Time Protocol
135	Microsoft RPC EPMAP	TCP, UDP	Microsoft Remote Procedure Call (RPC) Endpoint Mapper (EPMAP) service, for remote system access and management
137	NetBIOS-ns	TCP, UDP	NetBIOS Name Service, used for name registration and resolution
138	NetBIOS-dgm	TCP, UDP	NetBIOS Datagram Service, used for providing access to shared resources
139	NetBIOS-ssn	TCP, UDP	NetBIOS Session Service
143	IMAP	TCP, UDP	Internet Message Access Protocol (IMAP), management of electronic mail messages on a server
161	SNMP-agents (unencrypted)	UDP	Simple network management protocol; agents communicate on this port
162	SNMP-trap (unencrypted)	UDP	Simple network management protocol; listens for asynchronous traps
179	BGP	TCP	Border Gateway Protocol
194	IRC	UDP	Internet Relay Chat
264	BGMP	TCP, UDP	Border Gateway Multicast Protocol
318	TSP	TCP, UDP	Time Stamp Protocol
389	LDAP	TCP, UDP	Lightweight directory access protocol
427	SLP	TCP	Service Location Protocol
443	HTTPS (HTTP over SSL)	TCP, UDP, SCTP	Hypertext Transfer Protocol Secure (HTTPS) uses TCP in versions 1.x and 2. HTTP/3 uses QUIC, a transport protocol on top of UDP.
445	Microsoft DS SMB	TCP, UDP	Microsoft Directory Services: TCP for Active Directory, Windows shares; UDP for Server Message Block (SMB) file-sharing
464	Kerberos	TCP, UDP	For password settings on Kerberos
465	SMTP over TLS/SSL, SSM	TCP	Authenticated SMTP over TLS/SSL (SMTPS), URL Rendezvous Directory for Cisco’s Source Specific Multicast protocol (SSM)
497	Dantz Retrospect	TCP, UDP	A software suite for backing up operating systems
500	IPSec / ISAKMP / IKE	UDP	Internet Protocol Security / Internet Security Association and Key Management Protocol / Internet Key Exchange
513	rlogin	TCP	The Unix program rlogin allows users to log in on another host using a network.
514	syslog	UDP	Syslog Protocol, for collecting and organizing all of the log files sent from the various devices on a network
515	LPD/LPR	TCP	Line Printer Daemon protocol, or Line Printer Remote protocol
520	RIP	UDP	Routing Information Protocol, used to find the optimal path between source and destination networks
521	RIPng (IPv6)	UDP	Routing Information Protocol next generation, the IPv6 compatible version of RIP
554	RTSP	TCP, UDP	Real Time Streaming Protocol
546	DHCPv6	TCP, UDP	Dynamic Host Configuration Protocol version 6. DHCPv6 Clients listen for DHCPv6 messages on UDP port 546.
547	DHCPv6	TCP, UDP	DHCPv6 Servers and DHCPv6 Relay Agents listen for DHCPv6 messages on UDP port 547.
560	rmonitor	UDP	Remote Monitor
563	NNTP over TLS/SSL	TCP, UDP	Network News Transfer Protocol with encryption and verification
587	SMTP	TCP	For email message submission via SMTP
636	LDAP over TLS/SSL	TCP, UDP	Lightweight Directory Access Protocol over TLS/SSL
639	MSDP (PIM)	TCP	Multicast Source Discovery Protocol, which is part of the Protocol Independent Multicast (PIM) family
646	LDP (MPLS)	TCP, UDP	Label Distribution Protocol, applies to routers capable of Multiprotocol Label Switching (MPLS)
691	Microsoft Exchange	TCP	Microsoft Exchange Routing
860	iSCSI	TCP	Internet Small Computer Systems Interface
873	rsync	TCP	The rsync file synchronization protocol efficiently transfers and synchronizes files between devices and networked computers.
902	VMware Server	TCP, UDP	VMware ESXi, a hypervisor
989	FTPS	TCP	File Transfer Protocol (data) over TLS/SSL
990	FTPS	TCP	File Transfer Protocol (control) over TLS/SSL
993	IMAP over SSL (IMAPS)	TCP	Internet Message Access Protocol over TLS/SSL
995	POP3 over SSL (POP3S)	TCP, UDP	Post Office Protocol 3 over TLS/SSL