Common Port Numbers
A port number identifies a service on a host. Ports 0 to 1023 are the "well-known" ports; 1024 to 49151 are registered; the rest are dynamic. The service names below come from the IANA registry. Where real-world use differs from the registry we say so, because many ports are used by convention without being assigned.
| Port | IANA service | Protocols | Typical use |
|---|---|---|---|
| 20 | ftp-data | SCTP, TCP, UDP | FTP data channel (active mode). |
| 21 | ftp | SCTP, TCP, UDP | FTP control channel. Sends credentials in clear text unless wrapped in TLS. |
| 22 | ssh | SCTP, TCP, UDP | Secure Shell: remote login, command execution and file transfer (SFTP, SCP). |
| 23 | telnet | TCP, UDP | Telnet: unencrypted remote login. Replaced by SSH. |
| 25 | smtp | TCP, UDP | Server-to-server email delivery (SMTP). |
| 53 | domain | TCP, UDP | DNS queries. UDP for most queries, TCP for large responses and zone transfers. |
| 67 | bootps | TCP, UDP | DHCP server port (bootps). |
| 68 | bootpc | TCP, UDP | DHCP client port (bootpc). |
| 80 | http, www, www-http | SCTP, TCP, UDP | Unencrypted web traffic (HTTP). |
| 110 | pop3 | TCP, UDP | Email retrieval with POP3, unencrypted. |
| 123 | ntp | TCP, UDP | Network Time Protocol: clock synchronization. |
| 143 | imap | TCP | Email retrieval with IMAP, unencrypted or upgraded with STARTTLS. |
| 161 | snmp | TCP, UDP | SNMP queries for network device monitoring. |
| 162 | snmptrap | TCP, UDP | SNMP traps sent by devices to a manager. |
| 389 | ldap | TCP, UDP | Directory access with LDAP, used by Active Directory. |
| 443 | https | SCTP, TCP, UDP | Encrypted web traffic (HTTPS). Also carries QUIC and HTTP/3 over UDP. |
| 445 | microsoft-ds | TCP, UDP | SMB file sharing on Windows, without NetBIOS. |
| 465 | urd, submissions, igmpv3lite | TCP, UDP | Email submission over implicit TLS (SMTPS). IANA lists it today as 'submissions' (RFC 8314), alongside older entries. |
| 514 | shell, syslog | TCP, UDP | Syslog over UDP. IANA lists TCP 514 as the 'shell' service (rsh). |
| 587 | submission | TCP, UDP | Email submission from clients to a mail server, usually with STARTTLS. |
| 636 | ldaps | TCP, UDP | LDAP over TLS (LDAPS). |
| 853 | domain-s | TCP, UDP | DNS over TLS. |
| 873 | rsync | TCP, UDP | rsync file synchronization. |
| 993 | imaps | TCP | IMAP over implicit TLS. |
| 995 | pop3s | TCP, UDP | POP3 over implicit TLS. |
| 1433 | ms-sql-s | TCP, UDP | Microsoft SQL Server default instance. |
| 1521 | ncube-lm | TCP, UDP | Oracle Database listener by convention. IANA lists the port for nCube License Manager. |
| 2049 | shilp, nfs | TCP, UDP, SCTP | NFS network file system. |
| 3306 | mysql | TCP, UDP | MySQL and MariaDB. |
| 3389 | ms-wbt-server | TCP, UDP | Windows Remote Desktop (RDP). |
| 5432 | postgresql | TCP, UDP | PostgreSQL. |
| 5900 | rfb | TCP, UDP | VNC remote desktop (display 0). |
| 6379 | redis | TCP | Redis. |
| 8080 | http-alt | TCP, UDP | Common alternative HTTP port for proxies and development servers. |
| 8443 | pcsync-https | TCP, UDP | Common alternative HTTPS port. IANA lists it as 'pcsync-https'. |
| 9200 | wap-wsp | TCP, UDP | Elasticsearch HTTP API by convention. IANA lists the port for WAP connectionless session service. |
| 11211 | memcache | TCP, UDP | Memcached. |
| 27017 | mongodb | TCP | MongoDB. |
| 51820 | not registered | — | WireGuard VPN by convention. Not registered with IANA. |
Reading the table
- Registered means IANA lists a service name for the port. It does not mean the service is safe or recommended.
- Not registered ports, such as 51820 for WireGuard, are common by convention only.
- Exposing a port to the internet does not make a service reachable unless a process listens on it and a firewall allows it.
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