Port 3618: AAIR-Network 1 — A Name Without a Story

What Port 3618 Is

Port 3618 is a registered port, meaning it falls in the range from 1024 to 49151 — the band IANA manages for services that request an official assignment. Unlike well-known ports below 1024 (which require root/administrator privileges to bind), registered ports can be used by any application.

IANA's registry lists port 3618 as aairnet-1 (AAIR-Network 1), on both TCP and UDP.¹ That registration is where the trail goes cold. There is no RFC, no public specification, no company documentation, and no active community discussing this protocol. Whatever AAIR-Network was, it didn't leave much behind.

Port 3619 carries the companion entry "aairnet-2," which suggests a multi-port service — but the documentation gap is identical.

What You'll Actually Find on Port 3618

In practice, if you see traffic on port 3618, it almost certainly isn't AAIR-Network. Registered ports are not exclusive in the way a domain name is exclusive. Any application can bind to any port. Common real-world causes of activity on obscure registered ports include:

• Custom application servers that picked a port somewhat arbitrarily
• Development environments using it as a default for local services
• Database connectors, game servers, or proprietary enterprise tools that chose this range to avoid conflicts with well-known services

If you see port 3618 open on a system you manage, the IANA name won't tell you what's there. You have to look directly.

How to Check What's Listening

On any system you have access to, these commands reveal what process has claimed port 3618:

Linux / macOS:

# Show which process is bound to port 3618
ss -tlnp | grep 3618

# Alternative using lsof
lsof -i :3618

Windows:

# Show listening ports and associated process IDs
netstat -ano | findstr :3618

# Then look up the process by PID
tasklist | findstr <PID>

From a remote machine, you can check whether the port is open (without knowing what's behind it):

nc -zv <target-ip> 3618

Why These Gaps Exist

The registered port range was built on good intentions: if every service claims a port number officially, applications can coexist without colliding. In practice, the registry became a mix of actively used assignments, abandoned registrations from companies that no longer exist, and entries like this one — names with no body.

IANA processes registration requests, but doesn't require ongoing documentation or validation. A service registered in 1999 by a company that dissolved in 2003 keeps its entry forever. The name stays; the context evaporates.

Port 3618 is one of hundreds like it: officially occupied, functionally unclaimed, available to whoever needs it on any given server.