CyberHunter
Local dataset, no network
// Other services

Port 3671: e Field Control (EIBnet)

Port 3671 is assigned by IANA to efcp (e Field Control (EIBnet)).

3671

How efcp works

Other services
client:3671efcpresponse client:3671efcpresponse

The client sends a request to port 3671 and the efcp service answers.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
Category
Other services
01 Security

Is port 3671 dangerous?

We have no specific security note for port 3671. Its risk depends on the program actually listening on it. General advice for other services services:

  • Close the port if nothing on the host needs it.
  • Identify the process that listens on it (commands below) before opening it in a firewall.
  • Expose a service only to the networks that use it.
02 Registry

IANA registry entries for port 3671

ServicePortTransportDescriptionReferenceUpdated
efcp 3671 TCP, UDP e Field Control (EIBnet) - 2003-01

// source: IANA service name and port number registry

03 Check it

Which program uses port 3671, and is it reachable?

Linux

sudo ss -ltnup 'sport = :3671'      # process listening on 3671
sudo lsof -nP -i :3671

macOS

sudo lsof -nP -i :3671

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 3671 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 3671
netstat -ano | findstr :3671

From another machine

nmap -p 3671 -sV <host>
sudo nmap -sU -p 3671 <host>
nc -zv <host> 3671

Block it in the firewall

sudo ufw deny 3671/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 3671" -Direction Inbound -LocalPort 3671 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 3671 used for?

Port 3671 is assigned by IANA to efcp (e Field Control (EIBnet)).

Is port 3671 TCP or UDP?

Port 3671 is registered for TCP and UDP.

Is it safe to open port 3671?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Close the port if nothing on the host needs it.

How do I check if port 3671 is open?

On Linux run "ss -ltnup 'sport = :3671'", on macOS "lsof -nP -i :3671", and on Windows "netstat -ano | findstr :3671" to see the local process. From another machine, "nmap -p 3671 <host>" shows whether it is reachable.

05 Related
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