Report this

What is the reason for this report?

Port Ranges Set to DENY in UFW (Firewall) are Still Allowing Traffic on Those Ports

Posted on February 3, 2022

Here is a screen grab of ‘grep “Failed password” /var/log/auth.log’ for reference: https://imgur.com/a/G2bwrZO

I have the port range 30999:59999 set to DENY IN from ANYWHERE for udp and tcp traffic, yet I’m still receiving login attempts within the ranges of blocked ports.

Can anybody spot a misconfiguration, or perhaps explain what I’m missing with UFW?



This textbox defaults to using Markdown to format your answer.

You can type !ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.

Hi there,

Those ports are the port on the clients that are trying to connect to your SSH service.

Most outgoing connections on a system are made from the upper port ranges. For example on Linux, outgoing ports are chosen from 32768 - 61000 by default.

So to prevent this from happening, you actually need to close down port 22 on your server.

You could do that and then only allow your own IP address to access that port.

Hope that this helps.

Best,

Bobby

The developer cloud

Scale up as you grow — whether you're running one virtual machine or ten thousand.

Start building today

From GPU-powered inference and Kubernetes to managed databases and storage, get everything you need to build, scale, and deploy intelligent applications.