CyberHunter
Local dataset, no network
// Other services

Port 4096: BRE (Bridge Relay Element)

Port 4096 is assigned by IANA to bre (BRE (Bridge Relay Element)).

4096

How bre works

Other services
client:4096breresponse client:4096breresponse

The client sends a request to port 4096 and the bre 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)
01 Security

Is port 4096 dangerous?

We have no specific security note for port 4096. 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 4096

ServicePortTransportDescriptionReferenceUpdated
bre 4096 TCP, UDP BRE (Bridge Relay Element) - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 4096, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4096'      # process listening on 4096
sudo lsof -nP -i :4096

macOS

sudo lsof -nP -i :4096

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4096 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4096
netstat -ano | findstr :4096

From another machine

nmap -p 4096 -sV <host>
sudo nmap -sU -p 4096 <host>
nc -zv <host> 4096

Block it in the firewall

sudo ufw deny 4096/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4096" -Direction Inbound -LocalPort 4096 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4096 used for?

Port 4096 is assigned by IANA to bre (BRE (Bridge Relay Element)).

Is port 4096 TCP or UDP?

Port 4096 is registered for TCP and UDP.

Is it safe to open port 4096?

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 4096 is open?

On Linux run "ss -ltnup 'sport = :4096'", on macOS "lsof -nP -i :4096", and on Windows "netstat -ano | findstr :4096" to see the local process. From another machine, "nmap -p 4096 <host>" shows whether it is reachable.

05 Related

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