See the change log at the end for a complete revision history.
First and foremost, use only uBlock Origin (uBO) by Raymond 'gorhill' Hill (here's the uBlock Origin page on the Firefox Add-ons website). There are many other clones and wannabes out there and i would highly recommend not using them.
Following are my personal preferences for setting up uBlock Origin. The configurations in the 2nd and 3rd columns of the table are intended to be used with the The Firefox Privacy Guide For Dummies! and the Firefox Configuration Guide for Privacy Freaks and Performance Buffs, respectively, the former of which does not rely on uMatrix and the latter of which does. In both cases the advanced mode of uBO is disabled because i felt it would be too overwhelming for 1st time users and followers of the 'dummy' guide and it isn't needed for followers of the advanced guide since all dynamic filtering is accomplished with uMatrix which offers more granular filtering. Keep in mind these are my personal preferences and by no means do i claim they're the best possible for every use case, however i like to think they are generally sensible.
Regardless of which guide you are following, it is essential that you read the uBlock wiki with the exception of the Advanced-user-features section. If you are not following either guide and not using uMatrix, i would highly suggest enabling the advanced mode option in uBO in order to leverage its dynamic filtering capability and reading the Advanced-user-features section of the wiki. The suggested configuration for this scenario is in the 4th column of the table.
Once uBO is installed, click its toolbar icon to reveal its popup user interface, then click the little sliders icon to reveal the "secret" Dashboard (i say "secret" because apparently quite a few people don't know it exists). These are the settings i recommend:
'Settings' tab settings
Settings not shown here are optional.
|Setting name||'Dummy' guide settings (without uMatrix)||Advanced guide settings (with uMatrix)||Advanced usage (without uMatrix)|
|Hide placeholders of blocked elements 1||disabled||optional||optional|
|Show the number of blocked requests on the icon||enabled||optional||optional|
|I am an advanced user 2||disabled||disabled||enabled|
|Disable hyperlink auditing||enabled||enabled||enabled|
|Prevent WebRTC from leaking local IP addresses||enabled||enabled||enabled|
|Block CSP reports||enabled||enabled||enabled|
|Disable cosmetic filtering||enabled||enabled||enabled|
|Block media elements larger than  KB||disabled||optional||optional|
|Block remote fonts 3||disabled||disabled||disabled|
 If you are new to uBO and content filtering, you should not enable this option. Not enabling it will sometimes provide a visual indication when something is blocked in a webpage in the form of an empty space.
 This option should not be enabled if you are using uMatrix to handle dynamic filtering. If you are following the The Firefox Privacy Guide For Dummies! and not using uMatrix, or otherwise using uBlock on its own, then it may be enabled only after reading the Advanced user features section of the uBO wiki.
 I do not suggest blocking remote fonts using this option as this will uglify many websites. An alternative to this option is presented below.
<noscript> HTML tags. The problem with this is that some page elements that might have been displayed had the
Next we want to temporarily enable the 'I am an advanced user' option after which a little gear icon will appear to the right of the "I am an advanced user" text. Click the icon to display some advanced settings and change
yes. Although there is no guarantee, when you start Firefox uBO will attempt to delay network requests until it is fully loaded. This is most useful if you exit Firefox with open tabs and have it set to restore your previous tabs on restart. If you are following one of my Firefox guides, don't forget to return to the Dashboard and disable the 'I am an advanced user' option.
'Filter Lists' tab settings
|Auto-update filter lists||enabled|
|Parse and enforce cosmetic filters||disabled|
|Ignore generic cosmetic filters||enabled|
|uBlock filters – Badware risks 1||enabled|
|uBlock filters – Privacy||enabled|
|uBlock filters – Resource abuse||enabled|
|uBlock filters – Unbreak||enabled|
|AdGuard Mobile Ads 2||disabled|
|AdGuard Tracking Protection||disabled|
|Fanboy’s Enhanced Tracking List||enabled|
|Malware Domain List||enabled|
|AdGuard Social Media||disabled|
|EasyList Cookie||optional 3|
|uBlock filters – Annoyances||enabled|
|Dan Pollock’s hosts file||disabled|
|Peter Lowe’s Ad and tracking server list||disabled|
 Optional for Linux users
 Enable if using Firefox on a mobile device
 Enabling this list will hide a lot of those idiotic cookie notices
Don't worry about the 'Regions, languages' section unless you browse sites in languages other than English in which case you'll want to enable those languages.
As of this writing you can find over 12 million filter lists on the FilterLists website, however i strongly advise to be very careful about what ones you add, if any. In my experience the default filter lists offered by uBO are quite sufficient for general web browsing and adding more will use more memory, slow things down and potentially break more webpages.
'My filters' tab settings
Instead of blocking remote fonts globally, i suggest adding the following to the 'My filters' tab which will allow 1st party fonts globally while blocking all 3rd party fonts except for the domains you specifically allow. Note that lines starting with an exclamation mark (
! ) are comments and are ignored by uBO:
! fonts: the following line will allow 1st party fonts globally while blocking all 3rd party fonts:
! to allow 3rd party fonts per domain:
! to allow 3rd party fonts for additional domains:
For more on font filtering see Blocking Web Fonts for Speed and Privacy | InfoSec.
'My rules' tab settings
If you are following the Firefox Configuration Guide for Privacy Freaks and Performance Buffs or otherwise using uBO on its own, and are not using uMatrix, and you have enabled the 'I am an advanced user' setting (there's no reason to enable this setting if using uMatrix to control dynamic filtering), i suggest making the following changes.
On the 'My rules' tab, you may want to delete the default
behind-the-scene rules and replace them with the following, however this will break some websites:
no-scripting: behind-the-scene true
no-large-media: behind-the-scene true
behind-the-scene * * block
If you are using the LocalCDN add-on you will need to add some rules to the 'My Rules' tab in the uBO Dashboard. The rules can be found in the preferences section of the LocalCDN add-on from where you will copy the rules specific to uBlock Origin. After copying the rules, paste them on a new, blank line in the 'Temporary rules' section of the 'My Rules' tab after which you need to save and commit the changes. When adding the rules, be sure to remove any conflicting rules for the same domains if there are any (there won't be if you're starting fresh).
If you are running uBO with the 'I am an advanced user' option selected in order to enable dynamic filtering, i recommend setting the following rules to block (red) in the global rules column and then allowing (noop/grey) these resources on an as-needed basis per domain in the local rules column:
- article first published
- added info regarding
- changed value of
- separated settings according the Firefox guide being followed
- added a table of contents
- misc. edits
cnameAliasListfrom uBO settings (depreciated)
- minor edits
- updated filter list settings
- minor edits
- removed Adblock Warning Removal List (thank you 'someone')
- changed 'I am an advanced user' setting from 'enabled' to 'disabled' for the 'Advanced guide settings' - i don't know why i ever had this set to 'enabled', especially for those using uMatrix, which is the case in the advanced guide
- removed filter lists no longer included with newest version of uBO - thanks to 'theltalpha'
- minor edits
- replaced reference to Decentraleyes with LocalCDN and added additional information
- removed information regarding the CSP (Content Security Policy) issue since this is fixed with Firefox v77
- corrected an error in the 'My rules tab settings' section - thanks to commenter 'Hash' for notifying me
- minor edits
- edited unclear/incorrect information
- added a 4th column to the 'Settings tab' section for advanced users not following either of my guides and using uBlock Origin without uMatrix
- misc. minor edits
- minor edit: expanded instructions for adding LocalCDN rules to uBO