- Require authentication on cameras and media servers.
- Keep IP cameras and recorders off the Internet; use a VPN for remote viewing.
- Update device firmware.
Port 4991: VITA Radio Transport
Port 4991 is assigned by IANA to vrt (VITA Radio Transport).
4991
How vrt works
Media & streamingThe device streams video frames over port 4991, continuously, as they are captured.
- 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
- Media & streaming
Is port 4991 dangerous?
We have no specific security note for port 4991. Its risk depends on the program actually listening on it. General advice for media & streaming services:
IANA registry entries for port 4991
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| vrt | 4991 | TCP, UDP | VITA Radio Transport | - | 2009-01-08 |
// source: IANA service name and port number registry
Which program uses port 4991, and is it reachable?
Linux
sudo ss -ltnup 'sport = :4991' # process listening on 4991
sudo lsof -nP -i :4991macOS
sudo lsof -nP -i :4991
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4991 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 4991 netstat -ano | findstr :4991
From another machine
nmap -p 4991 -sV <host> sudo nmap -sU -p 4991 <host> nc -zv <host> 4991
Block it in the firewall
sudo ufw deny 4991/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 4991" -Direction Inbound -LocalPort 4991 -Protocol TCP -Action Block # Windows
What is port 4991 used for?
Port 4991 is assigned by IANA to vrt (VITA Radio Transport).
Is port 4991 TCP or UDP?
Port 4991 is registered for TCP and UDP.
Is it safe to open port 4991?
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. Require authentication on cameras and media servers.
How do I check if port 4991 is open?
On Linux run "ss -ltnup 'sport = :4991'", on macOS "lsof -nP -i :4991", and on Windows "netstat -ano | findstr :4991" to see the local process. From another machine, "nmap -p 4991 <host>" shows whether it is reachable.