- 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 2517: H.323 Annex E Call Control Signalling Transport
Port 2517 is assigned by IANA to call-sig-trans (H.323 Annex E Call Control Signalling Transport).
2517
How call-sig-trans works
Voice & chatPort 2517 sets up the call (who calls whom), then the voice travels as a stream of audio packets.
- 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
- Voice & chat
Is port 2517 dangerous?
We have no specific security note for port 2517. Its risk depends on the program actually listening on it. General advice for voice & chat services:
IANA registry entries for port 2517
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| call-sig-trans | 2517 | TCP, UDP | H.323 Annex E Call Control Signalling Transport | - | 2013-01-31 |
// source: IANA service name and port number registry
Which program uses port 2517, and is it reachable?
Linux
sudo ss -ltnup 'sport = :2517' # process listening on 2517
sudo lsof -nP -i :2517macOS
sudo lsof -nP -i :2517
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2517 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 2517 netstat -ano | findstr :2517
From another machine
nmap -p 2517 -sV <host> sudo nmap -sU -p 2517 <host> nc -zv <host> 2517
Block it in the firewall
sudo ufw deny 2517/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 2517" -Direction Inbound -LocalPort 2517 -Protocol TCP -Action Block # Windows
What is port 2517 used for?
Port 2517 is assigned by IANA to call-sig-trans (H.323 Annex E Call Control Signalling Transport).
Is port 2517 TCP or UDP?
Port 2517 is registered for TCP and UDP.
Is it safe to open port 2517?
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 2517 is open?
On Linux run "ss -ltnup 'sport = :2517'", on macOS "lsof -nP -i :2517", and on Windows "netstat -ano | findstr :2517" to see the local process. From another machine, "nmap -p 2517 <host>" shows whether it is reachable.