Does the random port generator give me an unused port?

No. Every result is a well-known or registered port that a named service already uses. It cannot see your computer, so it cannot tell you whether a port is free there. For a free local port, choose a number above 1024 that is not on the list and check it with lsof or netstat.

How many ports are in the list?

58, from 7 (Echo) to 31337 (Back Orifice). You can draw between 1 and 10 per press, and each press reshuffles the whole list.

Why are trojan ports like 12345 and 31337 included?

Because they are standard exam material. NetBus, Sub7 and Back Orifice were the best-known remote-access trojans of the late 1990s, and recognizing their default ports in a scan is still taught in security courses.

Are these TCP or UDP ports?

The list shows numbers and service names only. Many services are TCP (SSH, HTTP, MySQL), some are UDP (TFTP, most Kerberos traffic) and a few use both (DNS). Check the protocol separately when writing firewall rules.

Can I generate a port number in a specific range?

Not with this tool. It has one setting, the count, and always draws from the same 58 entries. For arbitrary numbers in a range, use a plain random number generator.

Random Port Generator

Get one to ten random port numbers from a list of 58 well-known ports, each shown with the service that normally uses it.

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Enter a number from 1 to 10 and press the button. Each card shows a port number and the service that conventionally listens on it: 22 for SSH, 53 for DNS, 443 for HTTP over SSL, 3306 for MySQL, 5900 for VNC. The picks come from a fixed list of 58 well-known and registered ports, from 7 (Echo) up to 31337 (Back Orifice). This is a study and test-data tool, not a port scanner: it tells you what a port is normally used for, not whether it is open or free on your machine.

What is in the list

The 58 entries cover the ports that come up most in networking courses, firewall rules and server logs. Grouped roughly:

Group	Ports in the list
Classic internet services	7 Echo, 20/21 FTP, 22 SSH, 23 Telnet, 25 and 587 SMTP, 53 DNS, 69 TFTP, 80 HTTP, 110 POP3, 143 IMAP4, 443 HTTPS
Secure variants	465 SMTP over TLS, 636 LDAPS, 989/990 FTPS, 993 IMAPS, 995 POP3S
Windows and directory services	88 and 464 Kerberos, 135 EPMAP, 137/139 NetBIOS, 593 DCOM, 691 MS Exchange, 1025 Microsoft RPC
Databases	2483/2484 Oracle DB, 3306 MySQL, 5432 PostgreSQL
Admin, VPN and remote access	1194 OpenVPN, 2082/2083 cPanel, 5900 VNC, 902/8222 VMware Server, 10000 BackupExec, 9100 printer PDL
Games and media	1725 Steam, 3074 Xbox Live, 3724 World of Warcraft, 6881 and 6999 BitTorrent, 6970 QuickTime, 6665-6669 IRC
Historic trojans	12345 NetBus, 27374 Sub7, 31337 Back Orifice, 1337 WASTE

A few services appear twice because they legitimately use more than one port (FTP over SSL on 989 and 990, Kaspersky on 8086 and 8087). The trojan ports are in there on purpose: they are the ones security courses expect you to recognize on a scan.

Port ranges, briefly

TCP and UDP port numbers run from 0 to 65535 and IANA splits them into three bands.

0 to 1023, well-known ports. Reserved for core services; on Linux and macOS only root can bind to them. Most of this list lives here.
1024 to 49151, registered ports. Assigned to specific applications on request (MySQL's 3306, PostgreSQL's 5432, Steam's 1725) but usable by anything.
49152 to 65535, dynamic or ephemeral ports. Handed out by the operating system for the client side of a connection. Nothing in this list is from this range.

A port number by itself does not say TCP or UDP. DNS on 53 uses both, TFTP on 69 is UDP only, and SSH on 22 is TCP only. The generator shows the number and service name; the protocol is something to look up when you write the firewall rule.

What people use it for

Certification drills. CompTIA Network+, Security+ and CCNA all expect you to match ports to services from memory. Generate ten, cover the service names, and quiz yourself.
Firewall and ACL exercises. Instructors hand out a random set and ask students to write allow or deny rules for each, including the protocol.
Sample data. Fake server inventories, log lines and monitoring dashboards look right with real port numbers next to real service names. Combine with the Random IP Generator for the host column and the Random MAC Address Generator for a hardware layer.
Capture-the-flag warmups. Recognizing 31337 or 12345 in a scan result is a small but real skill, and the list includes the classics.

If you are looking for a port to run a local dev server on, this tool is the wrong shape: it only returns ports that something already claims. Pick any number above 1024 that is not on this list (8000, 8080, 3000 and 5173 are the usual habits) and check it is free with lsof -i :PORT or netstat. For other test values, the Random String Generator and Random API Key Generator sit alongside this one in all developer and test data tools.

Frequently asked questions

Does the random port generator give me an unused port?: No. Every result is a well-known or registered port that a named service already uses. It cannot see your computer, so it cannot tell you whether a port is free there. For a free local port, choose a number above 1024 that is not on the list and check it with lsof or netstat.
How many ports are in the list?: 58, from 7 (Echo) to 31337 (Back Orifice). You can draw between 1 and 10 per press, and each press reshuffles the whole list.
Why are trojan ports like 12345 and 31337 included?: Because they are standard exam material. NetBus, Sub7 and Back Orifice were the best-known remote-access trojans of the late 1990s, and recognizing their default ports in a scan is still taught in security courses.
Are these TCP or UDP ports?: The list shows numbers and service names only. Many services are TCP (SSH, HTTP, MySQL), some are UDP (TFTP, most Kerberos traffic) and a few use both (DNS). Check the protocol separately when writing firewall rules.
Can I generate a port number in a specific range?: Not with this tool. It has one setting, the count, and always draws from the same 58 entries. For arbitrary numbers in a range, use a plain random number generator.