Network ports and protocols
Find TCP and UDP ports, protocol uses, security considerations and troubleshooting references for network administration.
Port 20 — FTP Data
FTP data transfer in active mode.
ResourcePort 21 — FTP Control
FTP command and control connections.
ResourcePort 22 — SSH / SFTP
Secure remote administration and SFTP file transfer over SSH.
Protocol definition → ResourcePort 23 — Telnet
Legacy remote terminal access without native session encryption.
ResourcePort 25 — SMTP
SMTP message transport, mainly between mail servers.
Protocol definition → ResourcePort 53 — DNS
DNS name resolution over UDP and TCP, including TCP for zone transfers and some larger responses.
Protocol definition → ResourcePort 67 — DHCP Server
DHCP server requests and dynamic IP address assignment.
Protocol definition → ResourcePort 68 — DHCP Client
Client-side reception of DHCP replies and network configuration.
Protocol definition → ResourcePort 69 — TFTP
Simple file transfer, often used for network devices and PXE booting.
Protocol definition → ResourcePort 80 — HTTP
Web access without TLS encryption.
Protocol definition → ResourcePort 88 — Kerberos
Kerberos authentication and service tickets, especially in Active Directory.
Protocol definition → ResourcePort 110 — POP3
Retrieving email with POP3, without encryption by default.
Protocol definition → ResourcePort 123 — NTP
NTP time synchronization between devices, servers and workstations.
Protocol definition → ResourcePort 135 — Microsoft RPC Endpoint Mapper
Microsoft RPC Endpoint Mapper directs Windows clients to available RPC services.
ResourcePort 137 — NetBIOS Name Service
Legacy NetBIOS name registration and resolution over UDP.
ResourcePort 138 — NetBIOS Datagram
Legacy NetBIOS datagram exchanges, mainly on local Windows networks.
ResourcePort 139 — NetBIOS Session
Legacy SMB file sharing through NetBIOS sessions.
ResourcePort 143 — IMAP
IMAP access to server-side mailboxes, with STARTTLS when supported and enforced.
Protocol definition → ResourcePort 161 — SNMP
SNMP monitoring and polling of network devices.
Protocol definition → ResourcePort 162 — SNMP Trap
Receiving SNMP traps and notifications from monitored devices.
Protocol definition → ResourcePort 389 — LDAP
LDAP directory access, including Active Directory; CLDAP discovery can use UDP.
Protocol definition → ResourcePort 443 — HTTPS
Web access protected by TLS; HTTP/3 can also use UDP 443 with QUIC.
Protocol definition → ResourcePort 445 — SMB / CIFS
SMB file and printer sharing, including Windows network services.
Protocol definition → ResourcePort 465 — SMTPS
Authenticated SMTP submission using implicit TLS, when supported by the provider.
ResourcePort 500 — IKE / IPsec
IKE negotiation for IPsec VPN tunnels, often followed by NAT-T on UDP 4500.
ResourcePort 514 — Syslog
Sending device and application logs to a central Syslog collector.
ResourcePort 587 — SMTP Submission
Authenticated email submission by clients and applications, commonly with STARTTLS.
ResourcePort 631 — IPP
Internet Printing Protocol for submitting and managing network print jobs.
ResourcePort 636 — LDAPS
LDAP directory connections protected by TLS from the start of the connection.
Protocol definition → ResourcePort 853 — DNS over TLS
DNS queries protected by TLS.
Protocol definition → ResourcePort 993 — IMAPS
IMAP mailbox access protected by implicit TLS.
ResourcePort 995 — POP3S
POP3 email retrieval protected by implicit TLS.
ResourcePort 1194 — OpenVPN
Common default port for OpenVPN connections.
ResourcePort 1433 — Microsoft SQL Server
Connections to SQL Server instances using the standard TCP port.
ResourcePort 1521 — Oracle Database
Common port for the Oracle Database listener.
ResourcePort 1701 — L2TP
L2TP tunneling, commonly combined with IPsec.
ResourcePort 1723 — PPTP
Legacy PPTP VPN control connections.
ResourcePort 1812 — RADIUS Authentication
RADIUS authentication for Wi-Fi, VPN and network access control.
Protocol definition → ResourcePort 1813 — RADIUS Accounting
RADIUS accounting records for network access sessions.
Protocol definition → ResourcePort 2049 — NFS
NFS file sharing between clients and servers.
Protocol definition → ResourcePort 3306 — MySQL / MariaDB
Client connections to MySQL and MariaDB databases.
Protocol definition → ResourcePort 3389 — RDP
Microsoft Remote Desktop connections.
Protocol definition → ResourcePort 4500 — IPsec NAT-T
IPsec NAT Traversal encapsulates VPN traffic in UDP 4500 when NAT is present.
ResourcePort 5060 — SIP
SIP signaling, commonly without TLS on port 5060.
Protocol definition → ResourcePort 5061 — SIP TLS
SIP signaling protected by TLS.
Protocol definition → ResourcePort 5432 — PostgreSQL
Client connections to PostgreSQL databases.
Protocol definition → ResourcePort 5900 — VNC
VNC remote desktop access.
ResourcePort 5985 — WinRM HTTP
Windows remote administration using WinRM over HTTP.
Protocol definition → ResourcePort 5986 — WinRM HTTPS
Windows remote administration using WinRM over HTTPS.
Protocol definition → ResourcePort 6379 — Redis
Client connections to the Redis key-value data store.
Protocol definition → ResourcePort 8080 — Alternative HTTP
Alternative HTTP port commonly used by proxies, consoles and applications.
Protocol definition → ResourcePort 8443 — Alternative HTTPS
Alternative HTTPS port commonly used by administration consoles and applications.
Protocol definition → ResourcePort 9200 — Elasticsearch HTTP API
Common port for the Elasticsearch HTTP API.
ResourcePort 27017 — MongoDB
Common default port for MongoDB client connections.