NETWORK
Port number rangesWell-known, registered and dynamic ports
Port numbers run from 0 to 65535 and IANA divides them into three ranges: system or well-known ports 0–1023 (HTTP 80, HTTPS 443, SSH 22), registered ports 1024–49151 (assigned to specific applications on request) and dynamic or private ports 49152–65535, which clients use for the source side of connections.
The three ranges
| Range | Name | Assigned by | Typical contents |
|---|---|---|---|
| 0–1023 | System (well-known) | IANA, standards action or IESG review | Core internet services: HTTP, HTTPS, SSH, DNS, SMTP, NTP, LDAP, SMB |
| 1024–49151 | User (registered) | IANA on request from developers | Databases, games, management consoles, proprietary protocols |
| 49152–65535 | Dynamic (private, ephemeral) | Nobody | Client-side source ports; see ephemeral ports |
A port number identifies a socket on a host; combined with the IP address and transport it uniquely names one endpoint of a connection.
What registration is and is not
IANA's registry is a coordination list. A registered entry means a developer asked for the number and IANA recorded the service name, so that other developers can avoid it. Registration does not reserve the port technically; operating systems enforce nothing except the Unix privilege rule for ports below 1024. Consequently:
- Some registered ports are used almost exclusively for something else (8443, 3000, 1521).
- Some heavily used ports were never registered for their real use.
- Port scanners that print the registered name are describing the registry, not the program actually listening.
The Port Lookup tool shows the registry entry alongside BlackhawkHub's own record where one exists.
Common well-known ports
| Port | Service | Transport |
|---|---|---|
| 20, 21 | FTP data, FTP control | TCP |
| 22 | SSH, SFTP | TCP |
| 23 | Telnet | TCP |
| 25 | SMTP relay | TCP |
| 53 | DNS | UDP, TCP |
| 67, 68 | DHCP | UDP |
| 80 | HTTP | TCP |
| 88 | Kerberos | TCP, UDP |
| 110 | POP3 | TCP |
| 123 | NTP | UDP |
| 135 | RPC endpoint mapper | TCP |
| 137–139 | NetBIOS | UDP, TCP |
| 143 | IMAP | TCP |
| 161, 162 | SNMP | UDP |
| 389 | LDAP | TCP, UDP |
| 443 | HTTPS | TCP, UDP (HTTP/3) |
| 445 | SMB | TCP |
| 465 | SMTP submission (TLS) | TCP |
| 514 | Syslog | UDP, TCP |
| 587 | SMTP submission | TCP |
| 636 | LDAPS | TCP |
| 993 | IMAPS | TCP |
| 995 | POP3S | TCP |
Common registered ports
| Port | Service |
|---|---|
| 1194 | OpenVPN |
| 1433 | Microsoft SQL Server |
| 1521 | Oracle listener |
| 1723 | PPTP |
| 1812 | RADIUS |
| 3000 | Node.js / Grafana |
| 3306 | MySQL |
| 3389 | RDP |
| 5060 | SIP |
| 5432 | PostgreSQL |
| 5900 | VNC |
| 5985 | WinRM |
| 6379 | Redis |
| 8080 | HTTP alternate |
| 8443 | HTTPS alternate |
| 27017 | MongoDB |
The full set of BlackhawkHub port records is on the ports index.
Frequently asked questions
Why do ports below 1024 need administrator rights?
On Unix-like systems only root (or a process with CAP_NET_BIND_SERVICE) can bind ports below 1024, a convention meant to guarantee that a well-known service is run by the system, not a user. Windows has no such restriction, which is why IIS and other services bind 80 without special handling.
Does registration mean a port can only be used for that service?
No. Registration records the intended use so that applications avoid collisions. Any program can bind any free port. Port 8443 is registered to pcsync-https and used almost universally for HTTPS alternates.
Are TCP and UDP port numbers the same list?
They are separate 65,536-entry spaces. IANA usually assigns the same number to a service for both transports to keep things simple, but TCP 53 and UDP 53 are different sockets.