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// Other services

Port 9122: Global Relay compliant mobile instant messaging protocol

Port 9122 is assigned by IANA to grcmp (Global Relay compliant mobile instant messaging protocol).

9122

How grcmp works

Other services
client:9122grcmpresponse client:9122grcmpresponse

The client sends a request to port 9122 and the grcmp service answers.

Transport
TCP
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 9122 dangerous?

We have no specific security note for port 9122. 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 9122

ServicePortTransportDescriptionReferenceUpdated
grcmp 9122 TCP Global Relay compliant mobile instant messaging protocol - 2025-06-12
-9122-Reserved--

// source: IANA service name and port number registry

03 Check it

Which program uses port 9122, and is it reachable?

Linux

sudo ss -ltnup 'sport = :9122'      # process listening on 9122
sudo lsof -nP -i :9122

macOS

sudo lsof -nP -i :9122

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 9122 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 9122
netstat -ano | findstr :9122

From another machine

nmap -p 9122 -sV <host>
nc -zv <host> 9122

Block it in the firewall

sudo ufw deny 9122/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 9122" -Direction Inbound -LocalPort 9122 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 9122 used for?

Port 9122 is assigned by IANA to grcmp (Global Relay compliant mobile instant messaging protocol).

Is port 9122 TCP or UDP?

Port 9122 is registered for TCP.

Is it safe to open port 9122?

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 9122 is open?

On Linux run "ss -ltnup 'sport = :9122'", on macOS "lsof -nP -i :9122", and on Windows "netstat -ano | findstr :9122" to see the local process. From another machine, "nmap -p 9122 <host>" shows whether it is reachable.

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