Network Ports Database

Detailed descriptions of well-known TCP/UDP ports — what they do, how safe they are and when they are used.

Security level: Safe Restricted Dangerous Deprecated

Email 7 ports

Email transmission between mail servers

Download email from server without encryption (POP3)

Server-side email management without encryption (IMAP)

Encrypted email submission via implicit TLS (SMTPS)

SMTP-Submission

Authenticated email submission from client to mail server (STARTTLS)

Encrypted IMAP email access over TLS (IMAPS)

Encrypted POP3 email retrieval over TLS (POP3S)

Web 6 ports

Unencrypted web traffic (HTTP)

Encrypted web traffic (HTTPS / TLS)

Flask development server or UPnP control port

Alternate HTTP port for development servers

Alternate HTTP port — Tomcat, proxies, and application servers

Alternate HTTPS port for secondary services

DNS & Network 3 ports

Domain and IP registration information lookup (WHOIS)

Resolves domain names to IP addresses (DNS)

Automatic local network device discovery (mDNS / Bonjour)

Databases 13 ports

Microsoft SQL Server database

SQL Server Browser — instance discovery service

Oracle Database server (TNS Listener)

MySQL and MariaDB database server

PostgreSQL relational database server

Apache CouchDB document database with HTTP REST API

Redis in-memory cache and data structure store

Elasticsearch HTTP REST API for search and analytics

Elasticsearch-cluster

Elasticsearch inter-node cluster communication

Memcached distributed in-memory caching system

MongoDB NoSQL document database

MongoDB shard server for horizontally scaled clusters

MongoDB config server storing sharding metadata

Remote Access 4 ports

Encrypted remote shell and file transfer (SSH)

Obsolete unencrypted remote terminal protocol

Windows Remote Desktop graphical remote access (RDP)

Graphical remote desktop access (VNC)

File Transfer 7 ports

FTP data transfer channel

FTP control channel for commands and responses

Simple file transfer with no authentication (TFTP)

Windows file sharing over NetBIOS (legacy SMB)

Windows file and printer sharing (SMB)

Shared filesystems between Unix/Linux systems (NFS)

BitTorrent peer-to-peer file sharing

VPN & Security 6 ports

IPsec VPN key negotiation (IKE / IKEv2)

OpenVPN — widely used open-source VPN protocol

L2TP VPN tunneling protocol, typically combined with IPsec

PPTP VPN — legacy and cryptographically broken VPN protocol

IPsec NAT traversal — allows IPsec through NAT routers

WireGuard — modern, fast, and lean VPN protocol

Monitoring & Management 14 ports

Monitoring and management of network devices (SNMP)

SNMP trap receiver — unsolicited alerts from network devices

Send system logs to a central log server (Syslog)

IPMI out-of-band server hardware management

cPanel web hosting control panel without SSL

cPanel web hosting control panel with SSL (HTTPS)

WHM server management panel without SSL

WHM server management panel with SSL (HTTPS)

Grafana monitoring dashboards or Node.js development server

Kibana — visualization and search UI for Elasticsearch

Encrypted syslog transport over TLS

Prometheus/Cockpit

Prometheus monitoring or Cockpit Linux web management

Prometheus Node Exporter — exposes host system metrics

Webmin web-based Linux/Unix server administration

Messaging & Chat 9 ports

Usenet newsgroup access (NNTP)

Real-time group chat protocol (IRC) — official IANA port

Lightweight publish-subscribe messaging for IoT devices (MQTT)

RabbitMQ message broker using the AMQP protocol

IRC server standard port — unencrypted

Encrypted IRC connections over SSL/TLS

MQTT over TLS — encrypted IoT messaging

Apache Kafka distributed event streaming platform

RabbitMQ Management Plugin web interface

DevOps & Containers 9 ports

Apache ZooKeeper distributed coordination service

Docker daemon API without encryption — extremely dangerous if exposed

Docker daemon API secured with TLS

etcd distributed key-value store — Kubernetes cluster state

Apache Subversion (SVN) version control

Kubernetes API server — central cluster control plane

Jupyter Notebook and JupyterLab interactive computing environment

SonarQube code quality analysis or PHP-FPM FastCGI

Native Git protocol for unauthenticated repository access

Network Protocols 15 ports

Automatic IP address assignment — DHCP server port

DHCP client port — receives IP configuration from server

Centralized ticket-based authentication (Kerberos)

Maps RPC services to their dynamic ports (portmapper)

Network time synchronization (NTP)

Microsoft RPC endpoint mapper — core Windows service

NetBIOS name resolution on Windows networks

NetBIOS datagram broadcasts on Windows networks

Inter-ISP routing protocol that connects the internet (BGP)

Directory services for users and resources (LDAP / Active Directory)

Network printing via IPP and CUPS

Encrypted LDAP directory access over TLS (LDAPS)

SOCKS proxy server for protocol-agnostic tunneling

Active Directory Global Catalog over LDAP

Active Directory Global Catalog over LDAPS (TLS)