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Port 6789 (radg)

IANA assigns port 6789 to radg: GSS-API for the Oracle Remote Administration Daemon.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference
radg TCP GSS-API for the Oracle Remote Administration Daemon Oracle 9 -

Registry dates for this port: registered 2002-08, last modified 2016-09-15.

Check what is listening on port 6789

Linux: is anything listening on TCP 6789?
sudo ss -tlnp 'sport = :6789'
Linux / macOS: which process owns the port
sudo lsof -nP -i :6789
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':6789 '
Windows (Command Prompt)
netstat -ano | findstr :6789
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 6789 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 6789
From Windows
Test-NetConnection HOST -Port 6789

Block port 6789 in the firewall

ufw
sudo ufw deny 6789/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 6789 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 6789 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 6789' -Direction Inbound -Protocol TCP -LocalPort 6789 -Action Block

Related ports

6787smc-admin6788smc-http6790hnmp6791hnm

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.