CyberHunter
Local dataset, no network
// Other services

Port 4001: NewOak

Port 4001 is assigned by IANA to newoak (NewOak).

4001

How newoak works

Other services
client:4001newoakresponse client:4001newoakresponse

The client sends a request to port 4001 and the newoak 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 4001 dangerous?

We have no specific security note for port 4001. 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 4001

ServicePortTransportDescriptionReferenceUpdated
newoak 4001 TCP, UDP NewOak - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 4001, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4001'      # process listening on 4001
sudo lsof -nP -i :4001

macOS

sudo lsof -nP -i :4001

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4001 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4001
netstat -ano | findstr :4001

From another machine

nmap -p 4001 -sV <host>
sudo nmap -sU -p 4001 <host>
nc -zv <host> 4001

Block it in the firewall

sudo ufw deny 4001/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4001" -Direction Inbound -LocalPort 4001 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4001 used for?

Port 4001 is assigned by IANA to newoak (NewOak).

Is port 4001 TCP or UDP?

Port 4001 is registered for TCP and UDP.

Is it safe to open port 4001?

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 4001 is open?

On Linux run "ss -ltnup 'sport = :4001'", on macOS "lsof -nP -i :4001", and on Windows "netstat -ano | findstr :4001" to see the local process. From another machine, "nmap -p 4001 <host>" shows whether it is reachable.

05 Related
:4444 Metasploit default / krb524 tcp · udp · high risk :31337 Back Orifice / elite tcp · udp · high risk :1 TCP Port Service Multiplexer tcp · udp :5 Remote Job Entry tcp · udp :9 Discard tcp · udp · sctp · dccp :11 Active Users tcp · udp :17 Quote of the Day tcp · udp :18 Message Send Protocol (historic) tcp · udp

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