CyberHunter
Local dataset, no network
// Other services

Port 4091: EminentWare Installer

Port 4091 is assigned by IANA to ewinstaller (EminentWare Installer).

4091

How ewinstaller works

Other services
client:4091ewinstallerresponse client:4091ewinstallerresponse

The client sends a request to port 4091 and the ewinstaller 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 4091 dangerous?

We have no specific security note for port 4091. 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 4091

ServicePortTransportDescriptionReferenceUpdated
ewinstaller 4091 TCP, UDP EminentWare Installer - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 4091, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4091'      # process listening on 4091
sudo lsof -nP -i :4091

macOS

sudo lsof -nP -i :4091

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4091 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4091
netstat -ano | findstr :4091

From another machine

nmap -p 4091 -sV <host>
sudo nmap -sU -p 4091 <host>
nc -zv <host> 4091

Block it in the firewall

sudo ufw deny 4091/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4091" -Direction Inbound -LocalPort 4091 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4091 used for?

Port 4091 is assigned by IANA to ewinstaller (EminentWare Installer).

Is port 4091 TCP or UDP?

Port 4091 is registered for TCP and UDP.

Is it safe to open port 4091?

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 4091 is open?

On Linux run "ss -ltnup 'sport = :4091'", on macOS "lsof -nP -i :4091", and on Windows "netstat -ano | findstr :4091" to see the local process. From another machine, "nmap -p 4091 <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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