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Port 4899 (radmin-port)

IANA assigns port 4899 to radmin-port: RAdmin Port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
radmin-port TCP RAdmin Port Dmitri Znosko -
radmin-port UDP RAdmin Port Dmitri Znosko -

Registry dates for this port: registered 2003-03.

Check what is listening on port 4899

Linux: is anything listening on TCP 4899?
sudo ss -tlnp 'sport = :4899'
Linux: UDP 4899
sudo ss -ulnp 'sport = :4899'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4899
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4899 '
Windows (Command Prompt)
netstat -ano | findstr :4899
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4899 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4899
From Windows
Test-NetConnection HOST -Port 4899
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4899

Block port 4899 in the firewall

ufw
sudo ufw deny 4899/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4899 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4899 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4899' -Direction Inbound -Protocol TCP -LocalPort 4899 -Action Block
ufw
sudo ufw deny 4899/udp
iptables
sudo iptables -A INPUT -p udp --dport 4899 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4899 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4899' -Direction Inbound -Protocol UDP -LocalPort 4899 -Action Block

Related ports

4889xcap-control4894lyskom4900hfcs4901flr-agent, flr_agent

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.