- 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 1990: cisco STUN Priority 1 port
Port 1990 is assigned by IANA to stun-p1 (cisco STUN Priority 1 port).
1990
How stun-p1 works
Voice & chatPort 1990 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 1990 dangerous?
We have no specific security note for port 1990. Its risk depends on the program actually listening on it. General advice for voice & chat services:
IANA registry entries for port 1990
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| stun-p1 | 1990 | TCP, UDP | cisco STUN Priority 1 port | - | - |
// source: IANA service name and port number registry
Which program uses port 1990, and is it reachable?
Linux
sudo ss -ltnup 'sport = :1990' # process listening on 1990
sudo lsof -nP -i :1990macOS
sudo lsof -nP -i :1990
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1990 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 1990 netstat -ano | findstr :1990
From another machine
nmap -p 1990 -sV <host> sudo nmap -sU -p 1990 <host> nc -zv <host> 1990
Block it in the firewall
sudo ufw deny 1990/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 1990" -Direction Inbound -LocalPort 1990 -Protocol TCP -Action Block # Windows
What is port 1990 used for?
Port 1990 is assigned by IANA to stun-p1 (cisco STUN Priority 1 port).
Is port 1990 TCP or UDP?
Port 1990 is registered for TCP and UDP.
Is it safe to open port 1990?
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 1990 is open?
On Linux run "ss -ltnup 'sport = :1990'", on macOS "lsof -nP -i :1990", and on Windows "netstat -ano | findstr :1990" to see the local process. From another machine, "nmap -p 1990 <host>" shows whether it is reachable.