HTTPfy

Port 3671 (efcp)

IANA assigns port 3671 to efcp: e Field Control (EIBnet).

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
efcp TCP e Field Control (EIBnet) Marc Goossens -
efcp UDP e Field Control (EIBnet) Marc Goossens -

Registry dates for this port: registered 2003-01.

Check what is listening on port 3671

Linux: is anything listening on TCP 3671?
sudo ss -tlnp 'sport = :3671'
Linux: UDP 3671
sudo ss -ulnp 'sport = :3671'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3671
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3671 '
Windows (Command Prompt)
netstat -ano | findstr :3671
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3671 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3671
From Windows
Test-NetConnection HOST -Port 3671
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3671

Block port 3671 in the firewall

ufw
sudo ufw deny 3671/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3671 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3671 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3671' -Direction Inbound -Protocol TCP -LocalPort 3671 -Action Block
ufw
sudo ufw deny 3671/udp
iptables
sudo iptables -A INPUT -p udp --dport 3671 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3671 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3671' -Direction Inbound -Protocol UDP -LocalPort 3671 -Action Block

Related ports

3669casanswmgmt3670smile3672lispworks-orb3673mediavault-gui

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