- Use strong credentials and TLS for signalling.
- Rate-limit registrations to stop extension scanning and toll fraud.
- Alert on unexpected chat protocols leaving servers (possible command and control).
Port 6817: PenTBox Secure IM Protocol
Port 6817 is assigned by IANA to pentbox-sim (PenTBox Secure IM Protocol).
6817
How pentbox-sim works
Voice & chatPort 6817 sets up the call (who calls whom), then the voice travels as a stream of audio packets.
- 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
- Voice & chat
Is port 6817 dangerous?
We have no specific security note for port 6817. Its risk depends on the program actually listening on it. General advice for voice & chat services:
IANA registry entries for port 6817
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| pentbox-sim | 6817 | TCP | PenTBox Secure IM Protocol | - | 2009-11-04 |
| - | 6817 | - | Reserved | - | - |
// source: IANA service name and port number registry
Which program uses port 6817, and is it reachable?
Linux
sudo ss -ltnup 'sport = :6817' # process listening on 6817
sudo lsof -nP -i :6817macOS
sudo lsof -nP -i :6817
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 6817 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 6817 netstat -ano | findstr :6817
From another machine
nmap -p 6817 -sV <host> nc -zv <host> 6817
Block it in the firewall
sudo ufw deny 6817/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 6817" -Direction Inbound -LocalPort 6817 -Protocol TCP -Action Block # Windows
What is port 6817 used for?
Port 6817 is assigned by IANA to pentbox-sim (PenTBox Secure IM Protocol).
Is port 6817 TCP or UDP?
Port 6817 is registered for TCP.
Is it safe to open port 6817?
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. Use strong credentials and TLS for signalling.
How do I check if port 6817 is open?
On Linux run "ss -ltnup 'sport = :6817'", on macOS "lsof -nP -i :6817", and on Windows "netstat -ano | findstr :6817" to see the local process. From another machine, "nmap -p 6817 <host>" shows whether it is reachable.