- Do not expose remote administration directly: use a VPN or a zero-trust access proxy.
- Require MFA or key-based authentication and lock out brute-force attempts.
- Log every login and alert on new source addresses.
Port 4899: RAdmin Port
Port 4899 is assigned by IANA to radmin-port (RAdmin Port).
4899
How radmin-port works
Remote accessThe client opens a session to port 4899: each command typed is sent to the server, which runs it and returns the output.
- 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
- Remote access
Is port 4899 dangerous?
We have no specific security note for port 4899. Its risk depends on the program actually listening on it. General advice for remote access services:
IANA registry entries for port 4899
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| radmin-port | 4899 | TCP, UDP | RAdmin Port | - | 2003-03 |
// source: IANA service name and port number registry
Which program uses port 4899, and is it reachable?
Linux
sudo ss -ltnup 'sport = :4899' # process listening on 4899
sudo lsof -nP -i :4899macOS
sudo lsof -nP -i :4899
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4899 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 4899 netstat -ano | findstr :4899
From another machine
nmap -p 4899 -sV <host> sudo nmap -sU -p 4899 <host> nc -zv <host> 4899
Block it in the firewall
sudo ufw deny 4899/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 4899" -Direction Inbound -LocalPort 4899 -Protocol TCP -Action Block # Windows
What is port 4899 used for?
Port 4899 is assigned by IANA to radmin-port (RAdmin Port).
Is port 4899 TCP or UDP?
Port 4899 is registered for TCP and UDP.
Is it safe to open port 4899?
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. Do not expose remote administration directly: use a VPN or a zero-trust access proxy.
How do I check if port 4899 is open?
On Linux run "ss -ltnup 'sport = :4899'", on macOS "lsof -nP -i :4899", and on Windows "netstat -ano | findstr :4899" to see the local process. From another machine, "nmap -p 4899 <host>" shows whether it is reachable.
Other remote access ports
:22 SSH tcp · udp · sctp · moderate risk :3389 RDP tcp · udp · critical risk :23 Telnet tcp · udp · critical risk :5900 VNC tcp · udp · critical risk :5985 WinRM (HTTP) tcp · udp · high risk :5986 WinRM (HTTPS) tcp · udp · high risk :10000 Webmin tcp · udp · high risk :89 SU/MIT Telnet Gateway tcp · udp