Hi buz3, I don't think Firefox has a built-in method to block IP addresses, but maybe the malware and phishing protection could be do it. To report a malware or phishing site, see these pages:

• https://safebrowsing.google.com/safebrowsing/report_badware/
• https://safebrowsing.google.com/safebrowsing/report_phish/

You might also double-check whether it could be related to one of your add-ons or settings:

Could you try:

New Profile Test

This takes about 3 minutes, plus the time to test connections.

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

Click the "Create a New Profile" button, then click Next. Assign a name like Oct2019, ignore the option to relocate the profile folder, and click the Finish button.

After creating the profile, scroll down to it and click the Launch profile in new browser button.

Firefox should open a new window that looks like a brand new, uncustomized installation. (Your existing Firefox window(s) should not be affected.) Please ignore any tabs enticing you to connect to a Sync account or to activate extensions found on your system so we can get a clean test.

Does Firefox connect to the unwanted site in the new profile?

When you are done with the experiment, you can close the extra window without affecting your regular Firefox profile. (Oct2019 will remain available for future testing.)

ok i try this. thx

if change profil this ip disconncet, but ..again connect in new profil

this bot net work only firefox..if try use firefox in my laptop this process is running connect to bot net.if try use my PC in firefox proccess runing and coonecting to bot net..if try use "seamonkey webbrowser" this process not see.

this bot net connect to firefoix network.

i found problem: this plugin connet to bot net

https://addons.mozilla.org/pl/firefox/addon/hma-vpn-proxy-unblock-websites/