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// Web

Port 3840: www.FlirtMitMir.de

Port 3840 is assigned by IANA to flirtmitmir (www.FlirtMitMir.de).

3840

How flirtmitmir works

Web
browser:3840flirtmitmir browser:3840flirtmitmir

A browser sends an HTTP request to port 3840 and the flirtmitmir server sends the page back.

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
Web
01 Security

Is port 3840 dangerous?

We have no specific security note for port 3840. Its risk depends on the program actually listening on it. General advice for web services:

  • Serve it over HTTPS only and check the HTTP security headers.
  • Keep admin consoles and development servers off the Internet.
  • Patch the application server and remove default credentials and sample apps.
02 Registry

IANA registry entries for port 3840

ServicePortTransportDescriptionReferenceUpdated
flirtmitmir 3840 TCP, UDP www.FlirtMitMir.de - 2003-11

// source: IANA service name and port number registry

03 Check it

Which program uses port 3840, and is it reachable?

Linux

sudo ss -ltnup 'sport = :3840'      # process listening on 3840
sudo lsof -nP -i :3840

macOS

sudo lsof -nP -i :3840

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 3840 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 3840
netstat -ano | findstr :3840

From another machine

nmap -p 3840 -sV <host>
sudo nmap -sU -p 3840 <host>
nc -zv <host> 3840

Block it in the firewall

sudo ufw deny 3840/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 3840" -Direction Inbound -LocalPort 3840 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 3840 used for?

Port 3840 is assigned by IANA to flirtmitmir (www.FlirtMitMir.de).

Is port 3840 TCP or UDP?

Port 3840 is registered for TCP and UDP.

Is it safe to open port 3840?

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. Serve it over HTTPS only and check the HTTP security headers.

How do I check if port 3840 is open?

On Linux run "ss -ltnup 'sport = :3840'", on macOS "lsof -nP -i :3840", and on Windows "netstat -ano | findstr :3840" to see the local process. From another machine, "nmap -p 3840 <host>" shows whether it is reachable.

05 Related
:443 HTTPS tcp · udp · sctp · low risk :80 HTTP tcp · udp · sctp · moderate risk :8080 HTTP alternate tcp · udp · high risk :8443 HTTPS alternate tcp · udp · moderate risk :3000 Dev servers / Grafana tcp · udp · moderate risk :5000 Flask / Docker registry / UPnP tcp · udp · moderate risk :8000 HTTP alternate (dev) tcp · udp · moderate risk :8888 Jupyter / HTTP alternate tcp · udp · high risk

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