N+ Ports and Protocols

FTP

Port 20/21 • TCP • File transfer. Port 21 is used for control; port 20 is traditionally used for data.

SFTP

Port 22 • TCP • Secure file transfer over SSH.

SSH

Port 22 • TCP • Secure encrypted remote command-line access.

Telnet

Port 23 • TCP • Insecure plaintext remote command-line access.

SMTP

Port 25 • TCP • Used for sending and transferring email, especially server-to-server.

DNS

Port 53 • UDP/TCP • Resolves domain names to IP addresses. UDP is common for normal queries; TCP is used when needed.

DHCP

Ports 67/68 • UDP • Dynamically assigns IP configuration. Server uses port 67; client uses port 68.

TFTP

Port 69 • UDP • Simple file-transfer protocol with no built-in authentication or encryption.

HTTP

Port 80 • TCP • Unencrypted web traffic.

NTP

Port 123 • UDP • Synchronizes clocks across network devices.

SNMP

Ports 161/162 • UDP • Used for network monitoring/management. Port 161 handles queries; port 162 receives traps/informs.

LDAP

Port 389 • TCP/UDP • Used to access directory services and directory information.

HTTPS

Port 443 • TCP • Encrypted HTTP web traffic protected by TLS.

SMB

Port 445 • TCP • Used primarily for Windows file and printer sharing.

Syslog

Port 514 • UDP/TCP • Sends log and event messages to a centralized logging server.

SMTPS

Port 587 • TCP • Secure/submission SMTP as listed by CompTIA.

LDAPS

Port 636 • TCP • LDAP protected by TLS/SSL.

SQL Server

Port 1433 • TCP • Default network port for Microsoft SQL Server.

RDP

Port 3389 • TCP/UDP • Microsoft protocol providing graphical remote desktop access.

SIP

Ports 5060/5061 • UDP/TCP • Used to initiate, manage, and terminate VoIP sessions. Port 5061 typically uses TLS.

TCP

Connection-oriented and reliable transport protocol. Provides sequencing, acknowledgments, retransmission, and flow control.

UDP

Connectionless, low-overhead transport protocol. Does not guarantee packet delivery or delivery order.

ICMP

Network-layer control and error-reporting protocol. Used by tools such as ping and traceroute/tracert.

GRE

Generic Routing Encapsulation. Encapsulates other network-layer protocols inside IP tunnels but does not provide encryption by itself.

IPsec

Secures IP traffic. AH provides integrity/authentication but not encryption; ESP provides encryption plus integrity/authentication; IKE negotiates keys and security associations.

Unicast

One source sends traffic to one specific destination.

Multicast

One source sends traffic to a selected group of destinations.

Anycast

Multiple devices can share the same address; routing delivers traffic to an appropriate or nearest instance.

Broadcast

One source sends traffic to all hosts in an IPv4 broadcast domain. IPv6 does not use normal broadcast traffic.