Look up what runs on a port number, or find the default port of a service. Filter the table by protocol, port range (well-known, registered, dynamic) or category such as web, mail, databases or remote access.
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Common TCP and UDP ports
Protocol
Description
Category
No ports match these filters. Try another name, or clear the filters.
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How to use the Common Ports List
Type a port number (like 3306) to see the services that use it, or a name (like postgres) to find its port.
Filter by protocol, port range or category to narrow the list.
Sort by clicking the Port or Service column header.
Read the description for what the service does and whether it is encrypted.
Copy or download: click a port number to copy it, or download the filtered table as a CSV file.
Port ranges defined by IANA
Range
Name
What it is for
0–1023
Well-known (system) ports
Core internet services such as HTTP, SSH, DNS and SMTP. Binding to them normally requires administrator rights.
1024–49151
Registered (user) ports
Assigned by IANA on request to specific applications, e.g. 3306 for MySQL or 3389 for RDP.
49152–65535
Dynamic / private ports
Never assigned. Used as short-lived source ports for outgoing connections and for private, temporary services.
The IANA "Service Name and Transport Protocol Port Number Registry" is the official list. Many ports in this table, such as 3000, 5173, 8000, 8080 or 9090, are popular defaults chosen by software projects rather than formal IANA assignments, so the same number can mean different things on different systems. Linux distributions often use their own ephemeral range of 32768–60999 instead of the IANA dynamic range.
Secure versions of common protocols
Plain text
Encrypted alternative
HTTP 80
HTTPS 443
FTP 21
SFTP 22 (over SSH) or FTPS 990
Telnet 23
SSH 22
SMTP 25 (between servers)
SMTP with STARTTLS on 25; client submission on 587 (STARTTLS) or 465 (implicit TLS)
POP3 110
POP3S 995
IMAP 143
IMAPS 993
LDAP 389
LDAPS 636
DNS 53
DNS over TLS 853 or DNS over HTTPS 443
MQTT 1883
MQTT over TLS 8883
How to check which ports are open
Linux:sudo ss -tulpn lists every listening TCP and UDP port with the program that owns it.
Windows:netstat -ano lists ports with process IDs; match them in Task Manager's Details tab.
Test a remote port:nc -zv example.com 443 on Linux/macOS, or Test-NetConnection example.com -Port 443 in PowerShell.
Frequently asked questions
What are well-known ports?
Ports 0 to 1023 are the well-known (system) ports assigned by IANA to core services such as HTTP (80), HTTPS (443), SSH (22) and DNS (53). On Linux and macOS, a program normally needs administrator rights to listen on them.
What is the difference between registered and dynamic ports?
Registered ports, 1024 to 49151, can be registered with IANA by software vendors, for example 3306 for MySQL. Dynamic or private ports, 49152 to 65535, are never assigned; operating systems use them as temporary (ephemeral) source ports for outgoing connections.
What is the difference between TCP and UDP ports?
TCP and UDP have separate port spaces of 65,536 numbers each. TCP provides reliable, ordered connections and is used for the web, email and SSH. UDP sends independent datagrams without delivery guarantees and suits DNS queries, voice, video and games. Many services register the same number on both.
Which port does HTTPS use?
HTTPS uses TCP port 443 by default. HTTP/3 also uses port 443, but over UDP with the QUIC protocol. Plain, unencrypted HTTP uses port 80.
Is a service always on its default port?
No. A port number is only a convention: administrators can run SSH on 2222 or a web app on 8080, and any program can listen on an unexpected port. To see what is actually listening on your machine, run sudo ss -tulpn on Linux or netstat -ano on Windows.
Which ports should I keep closed to the internet?
Expose only what you need, usually 80 and 443 for a web server. Never expose databases (3306, 5432, 27017, 6379), Docker's API (2375), RDP (3389), SMB (445) or Telnet (23) directly; reach them through a VPN or SSH tunnel instead.
How many ports are there?
Each of TCP and UDP has 65,536 ports, numbered 0 to 65535, because the port field in the packet header is 16 bits long. Port 0 is reserved and is not used for normal traffic.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.