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// Other services

Port 4101: Braille protocol

Port 4101 is assigned by IANA to brlp-0 (Braille protocol).

4101

How brlp-0 works

Other services
client:4101brlp-0response client:4101brlp-0response

The client sends a request to port 4101 and the brlp-0 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 4101 dangerous?

We have no specific security note for port 4101. 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 4101

ServicePortTransportDescriptionReferenceUpdated
brlp-0 4101 TCP, UDP Braille protocol - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 4101, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4101'      # process listening on 4101
sudo lsof -nP -i :4101

macOS

sudo lsof -nP -i :4101

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4101 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4101
netstat -ano | findstr :4101

From another machine

nmap -p 4101 -sV <host>
sudo nmap -sU -p 4101 <host>
nc -zv <host> 4101

Block it in the firewall

sudo ufw deny 4101/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4101" -Direction Inbound -LocalPort 4101 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4101 used for?

Port 4101 is assigned by IANA to brlp-0 (Braille protocol).

Is port 4101 TCP or UDP?

Port 4101 is registered for TCP and UDP.

Is it safe to open port 4101?

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 4101 is open?

On Linux run "ss -ltnup 'sport = :4101'", on macOS "lsof -nP -i :4101", and on Windows "netstat -ano | findstr :4101" to see the local process. From another machine, "nmap -p 4101 <host>" shows whether it is reachable.

05 Related
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