Port 230 sits in limbo. It's part of the well-known ports range (0-1023), the space where IANA assigns ports to established Internet services. But port 230 was never assigned to anything. It's part of a reserved block—ports 225 through 241—that IANA set aside decades ago and never allocated.1
Reserved doesn't mean unused. It means unclaimed. And in that vacuum, other things moved in.
What Reserved Actually Means
When IANA marks a port as "Reserved," they're holding it back from regular assignment.2 These aren't assigned to services. They're kept available for future use, edge cases, or extending port ranges. Reserved ports require a Standards Action or IESG Approval to be officially assigned—a high bar that keeps them off-limits to normal service registration.2
But there's no firewall around reserved ports. Anyone can listen on port 230. Applications can use it. Malware can use it. The reservation exists in IANA's database, not in your network stack.
What Actually Uses Port 230
Dungeon Siege II
The most documented legitimate use of port 230 is Dungeon Siege II, a multiplayer fantasy RPG released in 2005. The game uses port 230 for both TCP and UDP connections when hosting multiplayer sessions.34 If you wanted to host a game over the Internet, you had to configure your router to forward port 230 to your machine.3
The game never asked IANA for permission. It just picked an open port and used it. That's how most unofficial port usage works.
The Skun Trojan
Port 230 TCP is also associated with malware. The Skun trojan—a piece of malicious software—uses port 230 to communicate with infected systems.5 Security databases flag it as a known threat. If you find port 230 open and listening on a system you're not intentionally running a game server on, that's worth investigating.
Why Reserved Ports Matter
Reserved ports are breathing room in the addressing system. The Internet Assigned Numbers Authority doesn't assign every port immediately because they don't know what future protocols will need. Reserving blocks like 225-241 gives them flexibility.2
But reservation is purely administrative. Your operating system doesn't know port 230 is reserved. Your router doesn't care. The TCP/IP stack will happily bind a service to port 230 if you tell it to. Reservation prevents official assignment collisions, not actual usage.
The result is a port that exists in two states: officially reserved by IANA, and informally colonized by games and malware.
How to Check What's Listening on Port 230
On Linux or macOS:
Or using netstat:
On Windows:
This will show if anything on your system is listening on port 230, and what process owns it.6 If you see something and you're not running Dungeon Siege II, investigate further. Run a security scan. Reserved ports don't protect you from malicious software.
The Pattern
Port 230 is part of a larger pattern in the port system. There are 1,024 well-known ports (0-1023). According to RFC 6335, approximately 76% of them were assigned when the RFC was written.2 That means roughly 245 ports in the well-known range are either unassigned or reserved.
These gaps exist for good reasons—future protocols, special cases, administrative flexibility. But gaps get filled. Applications need ports. Developers pick numbers that look available. Malware authors do the same. And reserved ports, sitting there unused, look exactly like available ports to anyone who isn't checking IANA's database first.
That's the reality of port 230. Officially reserved. Unofficially occupied. A reminder that the addressing system of the Internet is part careful planning, part land grab, and part ongoing negotiation between what the standards say and what the network actually does.
Was this page helpful?