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Port 4839 (varadero-2)

IANA assigns port 4839 to varadero-2: Varadero-2.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
varadero-2 TCP Varadero-2 Carlos Arteaga -
varadero-2 UDP Varadero-2 Carlos Arteaga -

Check what is listening on port 4839

Linux: is anything listening on TCP 4839?
sudo ss -tlnp 'sport = :4839'
Linux: UDP 4839
sudo ss -ulnp 'sport = :4839'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4839
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4839 '
Windows (Command Prompt)
netstat -ano | findstr :4839
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4839 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4839
From Windows
Test-NetConnection HOST -Port 4839
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4839

Block port 4839 in the firewall

ufw
sudo ufw deny 4839/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4839 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4839 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4839' -Direction Inbound -Protocol TCP -LocalPort 4839 -Action Block
ufw
sudo ufw deny 4839/udp
iptables
sudo iptables -A INPUT -p udp --dport 4839 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4839 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4839' -Direction Inbound -Protocol UDP -LocalPort 4839 -Action Block

Related ports

4837varadero-04838varadero-14840opcua-tcp, opcua-udp4841quosa

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