Port 9122 (grcmp)

IANA assigns port 9122 to grcmp: Global Relay compliant mobile instant messaging protocol.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference

grcmp TCP Global Relay compliant mobile instant messaging protocol Global Relay Communications Inc -

Registry dates for this port: registered 2012-11-28, last modified 2025-06-12.

Linux: is anything listening on TCP 9122?

sudo ss -tlnp 'sport = :9122'

Linux / macOS: which process owns the port

sudo lsof -nP -i :9122

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':9122 '

Windows (Command Prompt)

netstat -ano | findstr :9122

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 9122 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 9122

From Windows

Test-NetConnection HOST -Port 9122

ufw

sudo ufw deny 9122/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 9122 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 9122 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 9122' -Direction Inbound -Protocol TCP -LocalPort 9122 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.