Ports & Protocols

SSH

TCP 22; secure remote administration

Telnet

TCP 23; unencrypted remote terminal access

FTP

TCP 20/21; file transfer

SFTP

TCP 22; secure file transfer over SSH

FTPS

TCP 989/990 commonly; FTP secured with TLS

TFTP

UDP 69; simple file transfer, no authentication by default

RDP

TCP/UDP 3389; remote desktop access

HTTP

TCP 80; unencrypted web traffic

HTTPS

TCP 443; encrypted web traffic using TLS

DNS

TCP/UDP 53; domain name resolution

DHCP

UDP 67/68; automatic IP address assignment

LDAP

TCP/UDP 389; directory services and lookups

LDAPS

TCP 636; LDAP secured with TLS

Kerberos

TCP/UDP 88; network authentication, commonly in Windows domains

SMTP

TCP 25; sending and relaying email between mail servers

SMTP Submission

TCP 587; email submission, typically with STARTTLS

SMTPS

TCP 465; email submission using implicit TLS

POP3

TCP 110; email retrieval

POP3S

TCP 995; secure email retrieval over TLS

IMAP

TCP 143; email access and synchronization

IMAPS

TCP 993; secure IMAP over TLS

SNMP

UDP 161; network monitoring and device management queries

SNMP Traps

UDP 162; network device notifications

Syslog

UDP 514 commonly; centralized log forwarding

Syslog over TLS

TCP 6514 commonly; encrypted log forwarding

NTP

UDP 123; time synchronization

RADIUS

UDP 1812/1813; authentication and accounting

TACACS+

TCP 49; centralized authentication, authorization, and accounting for network devices

SMB

TCP 445; Windows file and printer sharing

Microsoft SQL Server

TCP 1433 commonly; database connections

MySQL

TCP 3306; database connections

PostgreSQL

TCP 5432; database connections

IKE/IPsec

UDP 500; VPN key exchange and negotiation

IPsec NAT_T

UDP 4500; IPsec VPN traffic through NAT

SIP

TCP/UDP 5060; VoIP session signaling

SIP over TLS

TCP 5061; encrypted VoIP session signaling

LDAP Global Catalog

TCP 3268; Active Directory forest

LDAP Global Catalog over TLS

TCP 3269; secure forest