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Port 4371 (l2c-control, l2c-disc)

IANA assigns port 4371 to l2c-control, l2c-disc: LAN2CAN Control.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
l2c-control TCP LAN2CAN Control
Modified: 21 January 2010 Phil Tolson -
l2c-disc UDP LAN2CAN Discovery Phil Tolson -

Registry dates for this port: registered 2008-07-07.

Check what is listening on port 4371

Linux: is anything listening on TCP 4371?
sudo ss -tlnp 'sport = :4371'
Linux: UDP 4371
sudo ss -ulnp 'sport = :4371'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4371
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4371 '
Windows (Command Prompt)
netstat -ano | findstr :4371
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4371 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4371
From Windows
Test-NetConnection HOST -Port 4371
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4371

Block port 4371 in the firewall

ufw
sudo ufw deny 4371/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4371 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4371 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4371' -Direction Inbound -Protocol TCP -LocalPort 4371 -Action Block
ufw
sudo ufw deny 4371/udp
iptables
sudo iptables -A INPUT -p udp --dport 4371 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4371 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4371' -Direction Inbound -Protocol UDP -LocalPort 4371 -Action Block

Related ports

4369Erlang Port Mapper (EPMD)4370elpro-tunnel, elpro_tunnel4372l2c-data4373remctl

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.