Port 229: Reserved — A Deliberate Vacancy

Port 229 is reserved. It doesn't carry a service, host a protocol, or listen for connections. It sits in a block of 17 ports (225-241) that the Internet Assigned Numbers Authority set aside in 1990 and has kept vacant ever since.¹

Not unassigned. Not forgotten. Reserved.

What "Reserved" Means

Port 229 belongs to the System Ports range (0-1023), also called the Well-Known Ports.² These ports are assigned by IANA through formal processes—IETF Review or IESG Approval—and they're meant for established, standardized Internet services.

But reserved ports are different. They're not available for assignment. They're held back.

IANA keeps certain port numbers reserved for special purposes: extending port ranges, accommodating future needs, administrative flexibility.³ Ports at the edges of ranges are often reserved (0, 1023, 1024). So are specific blocks like 225-241.

Port 229 is one of those deliberately vacant spaces.

The Context: Where Port 229 Sits

The ports around 229 tell you what this neighborhood was like:

• Port 224: masqdialer (MASQ Dial)
• Ports 225-241: Reserved
• Port 242: Direct (Direct)

The assigned ports bracket the reserved block. IANA drew a clear boundary: these 17 ports are off-limits.

Why Reserve Ports?

The Internet was smaller in 1990. The port number space seemed vast. But IANA knew something humans often forget: resources that seem infinite rarely are.

Reserved ports are strategic. They're held back for when the available pool runs out. They're insurance against future constraints.³

Port 229 has been sitting in reserve for over three decades. It might wait three more. Or it might be assigned tomorrow if IANA decides the need is urgent enough.

For now, it waits.

How to Check What's on Port 229

If you want to see if anything is listening on port 229 on your system:

Linux/Mac:

sudo lsof -i :229
# or
sudo netstat -tulpn | grep :229

Windows:

netstat -ano | findstr :229

You'll almost certainly find nothing. Reserved ports are rarely used in practice, and port 229 has no documented unofficial uses.

Why This Matters

Reserved ports are the Internet's version of "just in case." They're the empty seats at a crowded conference, the buffer in a tight schedule, the margin in a system running near capacity.

Port 229 doesn't do anything. But its vacancy is purposeful. In a port space where 65,535 numbers must serve billions of devices running millions of services, having a few numbers held in reserve is not waste—it's wisdom.

The port that carries nothing carries the possibility of everything.

Related Ports:

• Port 224 — masqdialer
• Port 242 — Direct