20FTP Data
FTP
File Transfer Protocol — data channel.
TCP
File transfer
Port Reference Lookup
Look up common services for any TCP/UDP port number
1 credit
52 matches
21FTP Control
FTP
File Transfer Protocol — command channel.
TCP
File transfer
22SSH
OpenSSH
Secure Shell — encrypted remote login + SFTP.
TCP
Remote access
23Telnet
Telnet
Unencrypted remote shell — avoid on the public net.
TCP
Remote access
25SMTP
Mail relay
Simple Mail Transfer — server-to-server relay.
TCP
Mail
53DNS
BIND / systemd-resolved
Domain Name System — name resolution.
TCP/UDP
DNS
67DHCP Server
DHCP
Bootstrap / DHCP — address assignment.
UDP
Other
68DHCP Client
DHCP
DHCP client — receives leases.
UDP
Other
69TFTP
TFTP
Trivial FTP — unauthenticated firmware transfers.
UDP
File transfer
80HTTP
Web server
HyperText Transfer Protocol — plaintext web.
TCP
Web
110POP3
Mail client
Post Office Protocol — download-and-delete mail.
TCP
Mail
123NTP
ntpd / chrony
Network Time Protocol — clock synchronization.
UDP
Other
143IMAP
Mail client
Internet Message Access — server-side mailbox.
TCP
Mail
161SNMP
SNMP
Simple Network Management — device monitoring.
UDP
Other
194IRC
IRC
Internet Relay Chat — classic chat protocol.
TCP
Messaging
389LDAP
OpenLDAP
Lightweight Directory Access — directory lookups.
TCP
Other
443HTTPS
Web server
HTTP over TLS — the encrypted public web.
TCP
Web
445SMB
Samba
Windows file + printer sharing over IP.
TCP
File transfer
465SMTPS
Mail submission
SMTP over TLS (implicit).
TCP
Mail
514Syslog
rsyslog
Classic syslog log collection.
UDP
Other
587SMTP Submit
Mail client
Authenticated mail submission (STARTTLS).
TCP
Mail
631IPP
CUPS
Internet Printing Protocol.
TCP
Other
636LDAPS
OpenLDAP
LDAP over TLS.
TCP
Security
853DNS-over-TLS
DoT resolver
Encrypted DNS via TLS.
TCP
DNS
993IMAPS
Mail client
IMAP over TLS.
TCP
Mail
995POP3S
Mail client
POP3 over TLS.
TCP
Mail
1080SOCKS
Proxy
SOCKS proxy protocol.
TCP
Other
1194OpenVPN
OpenVPN
OpenVPN server default.
UDP
Security
1433MSSQL
SQL Server
Microsoft SQL Server default port.
TCP
Database
1521Oracle DB
Oracle
Oracle Database default listener.
TCP
Database
2375Docker API
Docker
Docker remote daemon — unencrypted.
TCP
Dev / Build
2376Docker TLS
Docker
Docker remote daemon — TLS.
TCP
Dev / Build
3000Dev server
Next.js / Rails/Create-React-App
Common local dev server port.
TCP
Dev / Build
3306MySQL
MySQL
MySQL / MariaDB default port.
TCP
Database
3389RDP
Windows RDP
Remote Desktop Protocol.
TCP
Remote access
4000Phoenix / Vite
Phoenix / Vite HMR
Common Elixir / Vite dev port.
TCP
Dev / Build
5000Flask / UPnP
Flask / AirPlay
Python dev servers + macOS AirPlay receiver.
TCP
Dev / Build
5173Vite
Vite dev
Vite default dev server.
TCP
Dev / Build
5432PostgreSQL
PostgreSQL
PostgreSQL default port.
TCP
Database
5672AMQP
RabbitMQ
AMQP message broker.
TCP
Messaging
5900VNC
VNC
Virtual Network Computing display share.
TCP
Remote access
6379Redis
Redis
Redis / Valkey default.
TCP
Database
7000Cassandra
Cassandra
Cassandra inter-node.
TCP
Database
8000HTTP alt
Dev server
Python `http.server`, Django dev, etc.
TCP
Dev / Build
8080HTTP alt
Tomcat / proxies
Common alternative HTTP port.
TCP
Web
8443HTTPS alt
TLS alt
Alternative HTTPS port.
TCP
Web
8888Jupyter
Jupyter Notebook
Jupyter notebook server.
TCP
Dev / Build
9000PHP-FPM
PHP-FPM / SonarQube
PHP FastCGI + SonarQube.
TCP
Dev / Build
9092Kafka
Apache Kafka
Kafka broker.
TCP
Messaging
9200Elasticsearch
Elasticsearch / OpenSearch
ES/OpenSearch HTTP API.
TCP
Database
11211Memcached
memcached
Memory key-value cache.
TCP/UDP
Database
27017MongoDB
MongoDB
MongoDB default port.
TCP
Database