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// Other services

Port 1773: KMSControl

Port 1773 is assigned by IANA to kmscontrol (KMSControl).

1773

How kmscontrol works

Other services
client:1773kmscontrolresponse client:1773kmscontrolresponse

The client sends a request to port 1773 and the kmscontrol service answers.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
Category
Other services
01 Security

Is port 1773 dangerous?

We have no specific security note for port 1773. Its risk depends on the program actually listening on it. General advice for other services services:

  • Close the port if nothing on the host needs it.
  • Identify the process that listens on it (commands below) before opening it in a firewall.
  • Expose a service only to the networks that use it.
02 Registry

IANA registry entries for port 1773

ServicePortTransportDescriptionReferenceUpdated
kmscontrol 1773 TCP, UDP KMSControl - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 1773, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1773'      # process listening on 1773
sudo lsof -nP -i :1773

macOS

sudo lsof -nP -i :1773

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1773 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1773
netstat -ano | findstr :1773

From another machine

nmap -p 1773 -sV <host>
sudo nmap -sU -p 1773 <host>
nc -zv <host> 1773

Block it in the firewall

sudo ufw deny 1773/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1773" -Direction Inbound -LocalPort 1773 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 1773 used for?

Port 1773 is assigned by IANA to kmscontrol (KMSControl).

Is port 1773 TCP or UDP?

Port 1773 is registered for TCP and UDP.

Is it safe to open port 1773?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Close the port if nothing on the host needs it.

How do I check if port 1773 is open?

On Linux run "ss -ltnup 'sport = :1773'", on macOS "lsof -nP -i :1773", and on Windows "netstat -ano | findstr :1773" to see the local process. From another machine, "nmap -p 1773 <host>" shows whether it is reachable.

05 Related
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