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Port 3138 (rtnt-2)

IANA assigns port 3138 to rtnt-2: rtnt-2 data packets.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
rtnt-2 TCP rtnt-2 data packets Ron Muellerschoen -
rtnt-2 UDP rtnt-2 data packets Ron Muellerschoen -

Check what is listening on port 3138

Linux: is anything listening on TCP 3138?
sudo ss -tlnp 'sport = :3138'
Linux: UDP 3138
sudo ss -ulnp 'sport = :3138'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3138
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3138 '
Windows (Command Prompt)
netstat -ano | findstr :3138
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3138 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3138
From Windows
Test-NetConnection HOST -Port 3138
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3138

Block port 3138 in the firewall

ufw
sudo ufw deny 3138/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3138 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3138 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3138' -Direction Inbound -Protocol TCP -LocalPort 3138 -Action Block
ufw
sudo ufw deny 3138/udp
iptables
sudo iptables -A INPUT -p udp --dport 3138 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3138 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3138' -Direction Inbound -Protocol UDP -LocalPort 3138 -Action Block

Related ports

3136grubd3137rtnt-13139incognitorv3140ariliamulti

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