Hi   !

You could try this add-on :

https://addons.mozilla.org/en-US/firefox/addon/procon-latte/

ProCon can filter any kind of material (pornography, gambling, hacking, cracking, etc...), it can also block all traffic, making sure that only desired websites (those in the whitelist) can be accessed.

I don't know if this will still work with Firefox 57+, though ..... (You'd have to ask the developer to make sure it does)

Note : In Safe Mode add-ons are disabled.

I want to make a whitelist for two sites and blacklist rest of whole web, because i don't need them right now(maybe later).

milanmilano said

I want to make a whitelist for two sites and blacklist rest of whole web, because i don't need them right now(maybe later).

That's what the add-on is supposed to do .......

I found muting web extension, i just hope it works

Nope it cuts the sounds. By the way how i can block the whole web? There are several tags. Should i write http://www, or https..? These are filters? Help me

I didnt mention Proton about cutting the sounds. The other extension..

I did. With firefox connection settings i made whitelist. Thank you for help.

Here is my solution, here we go :

Options->Advanced->Network->Connections. After doing that, choose radio button (Manuel Proxy). Set HTTP proxy 0.0.0.0 , port doesnt matter.Check below "Use this proxy server for all protocols option. Then in the "No Proxy for" box, write down your whitelist. That's all. Click Ok.