What Port 3087 Is
Port 3087 sits in the registered ports range (1024–49151), the middle tier of the port numbering system. This range is where IANA tracks assignments for specific applications and services — not the globally universal well-known ports below 1024, but also not the ephemeral ports above 49151 that operating systems hand out temporarily for outgoing connections.
The registered range is large enough that many ports have legitimate assignments. Port 3087 is one of them, technically.
The Official Assignment: Asoki SMA
According to the IANA Service Name and Transport Protocol Port Number Registry, port 3087 is assigned to Asoki SMA on both TCP and UDP, registered by a contact named Andrew Mossberg.
That's where the trail ends.
There's no RFC. No public documentation. No open-source project, no product page, no forum thread from someone trying to configure it. The registration exists, and the service behind it — whatever "Asoki SMA" means — does not appear to have ever reached any kind of public deployment or visibility.
This happens. The IANA registration process requires a form and an intended purpose, but it doesn't require that your software ship, succeed, or survive. Port 3087 got a name, and the name outlasted whatever it was registered for.
Security: A Malware Address
Port 3087 does appear in one security context worth knowing about. The malware variant Backdoor.Win32.Mazben.es — a backdoor that functions as an unauthenticated open proxy — is known to listen on a rotation of ports including 3087.1 An infected machine becomes a relay: traffic flows through it, and the source appears to originate there instead of from the actual attacker.
If you see unexpected traffic on port 3087, especially inbound connections that your system has no business accepting, that's worth investigating.
How to See What's Using This Port
On any system, you can check what's actually listening:
Linux / macOS:
Windows:
If something is listening and you didn't put it there, find out what it is before assuming it's harmless.
Why Unassigned-in-Practice Ports Matter
The port registry serves a coordination function: if every application picked port numbers at random, conflicts would be constant. The registered range gives applications a place to stake a claim. But claiming a port and using it are different things.
Port 3087's registration is a placeholder for something that never materialized publicly. That makes it, in practice, open territory — available for internal tools, development servers, or anything else that needs a port and doesn't want to collide with something known. Just be aware that malware authors are familiar with obscure registered ports too. Obscurity is not security.
Czy ta strona była pomocna?