How to stop Firefox from making automatic connections
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- Revision id: 101114
- Created:
- Creator: philipp
- Comment: update on tiles behaviour
- Reviewed: No
- Ready for localization: No
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Some people are concerned about the connections Firefox makes to the Internet, especially when those connections are made for no apparent reason (see Mozilla's Firefox Browser Privacy Notice for additional information). This article explains various reasons why Firefox may make a connection to the Internet and how you can stop it from doing so, if you wish.
Table of Contents
Automatic updates and Security
Auto-update checking
Firefox occasionally checks to see if any updates are available for itself and for your search engines. To disable these checks:
- In the Menu bar at the top of the screen, click and then select or , depending on your macOS version.Click the menu button and select .
- Select the panel.
- Select the tab.
- Check Never check for updates (not recommended: security risk) and uncheck Search Engines. Close the about:preferences page.
Firefox also checks to see if any updates are available for your add-ons (extensions, themes). To disable this check:
- Click the menu button , click and select .
- At the top of the tab, click the "Tools for all add-ons" menu, uncheck Update Add-ons Automatically and then select Reset All Add-ons to Update Automatically.
Blocklist updating
Firefox may be updating its blocklist, which is used to block malicious extensions, vulnerable plugins, revoked certificates and graphics drivers known to cause crashes. For more information, see Blocklisting (MozillaWiki), Blocklisting/Graphics (MozillaWiki), the Revoking Intermediate Certificates: Introducing OneCRL blog post and the article Add-ons that cause stability or security issues are put on a blocklist. To disable this feature:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - In the about:config page, search for the preference extensions.blocklist.enabled.
- Observe the Value column of the extensions.blocklist.enabled row.
- If it is set to false then do nothing.
- If it is set to true, double-click on it to set it to false.
Anti-phishing list updating
The phishing protection list may be updating itself. To turn this off:
- In the Menu bar at the top of the screen, click and then select or , depending on your macOS version.Click the menu button and select .
- Select the panel.
- Uncheck Block reported web forgeries.
Anti-malware list updating
The malware protection list may be updating itself. To turn this off:
- In the Menu bar at the top of the screen, click and then select or , depending on your macOS version.Click the menu button and select .
- Select the panel.
- Uncheck Block reported attack sites.
In addition, when you download an application file, Firefox will verify its signature. If it is signed, Firefox then compares the signature with a list of known safe publishers. For files that are not identified by the lists as “safe” (allowed) or as “malware” (blocked), Firefox asks Google’s Safe Browsing service if the software is safe by sending it some of the download’s metadata. To turn off this part of malware protection:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - In the about:config page, search for the preference browser.safebrowsing.appRepURL.
- Double-click on it and set its value to a blank string.
Secure website certificates
When you visit a secure website (i.e. "https"), Firefox will validate the website's certificate. This may involve communicating with a third-party status provider specified by the certificate over a protocol namend OCSP to confirm that the certificate is still valid. To turn this off:
- In the Menu bar at the top of the screen, click and then select or , depending on your macOS version.Click the menu button and select .
- Select the panel.
- Select the tab.
- Uncheck Query OCSP responder servers to confirm the current validity of certificates.
Prefetching
Link prefetching
Firefox will prefetch certain links if any of the websites you are viewing uses the special prefetch-link tag. For more information, please see the Link Prefetching FAQ. To disable Link prefetching:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - In the about:config page, search for the preference network.prefetch-next.
- Observe the Value column of the network.prefetch-next row.
- If it is set to false then do nothing.
- If it is set to true, double-click on it to set it to false.
DNS prefetching
In order to reduce latency, Firefox will proactively perform domain name resolution on links that the user may choose to follow as well as URLs for items referenced by elements in a web page. For more information, please see the DNS Prefetching blog post. To disable DNS prefetching:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - In the about:config page, search for the preference network.dns.disablePrefetch.
- Observe the Value column of the network.dns.disablePrefetch row.
- If it is set to true then do nothing.
- If it is set to false, double-click on it to set it to true.
Speculative pre-connections
To improve the loading speed, Firefox will open predictive connections to sites when the user hovers their mouse over thumbnails on the New Tab Page or the user starts to search in the Search Bar, or in the search field on the Home or the New Tab Page. In case the user follows through with the action, the page can begin loading faster since some of the work was already started in advance. To disable this feature:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - In the about:config page, search for the preference network.http.speculative-parallel-limit.
- Observe the Value column of the network.http.speculative-parallel-limit row.
- If it is set to 0 then do nothing.
- If it is set to a different value, double-click on it to set it to 0.
Add-on list prefetching
Each time the Add-ons manager is opened, Firefox prefetches a list of add-ons to improve responsiveness of the
pane. This connection is not made if the add-ons manager is not opened.User-invoked content
Home page loading
Your home page may be loading. To change your home page to something that doesn't generate connections to the Internet:
- In the Menu bar at the top of the screen, click and then select or , depending on your macOS version.Click the menu button and select .
- Select the panel.
- Either set When Firefox starts to Show a blank page or set it to Show my home page and click Close the about:preferences page. .
Extensions
An extension you have installed may be making a connection to a website that it relies on. For example, a connection to a website to synchronize your bookmarks, a connection to a website to update a list of sites to block, etc. Or it is possible an extension could be changing the expected behavior of Firefox in other ways. For example, FasterFox extension has an option to prefetch all links. To easily disable all of your extensions please read the Diagnose Firefox issues using Troubleshoot Mode article, paying particular attention to the Disable all add-ons option under the section. To disable or remove your extensions, see the Disable or remove Add-ons article.
Firefox also checks to see if any updates are available for your add-ons (extensions, themes). To disable this check:
- Click the menu button , click and select .
- At the top of the tab, click the "Tools for all add-ons" menu, uncheck Update Add-ons Automatically and then select Reset All Add-ons to Update Automatically.
Live Bookmarks updating
Live Bookmarks automatically reload themselves on a regular basis, and in doing so will make a connection to the Internet. Deleting all your Live Bookmarks will stop these connections from being made.
Downloads restarted
When you start Firefox, any interrupted downloads from your previous browsing session may be automatically resumed.
- Press Ctrl + JCtrl + Shift + Ycommand + J to open the Downloads window.
- Ensure nothing is currently being downloaded.
Search plugin icon loading
When you add a custom search plugin that doesn't come with an included icon, Firefox might look up the icon at a remote address that is specified in the search plugin once and cache it for future use.
Firefox Sync
If you're using Firefox Sync, it will establish regular connections in order to synchronize your data to Mozilla's Sync servers and across your connected devices. In order to choose what data gets synchronized or to disconnect from Sync, see the How do I choose what information to sync on Firefox? article.
Firefox Hello
If you're using the Firefox Hello video and voice chat feature of the browser by signing in with a Firefox Account or starting a conversation, there will be a connection established in order to set up a call, once your conversation partner joins a conversation remotely. Besides signing out from Firefox Hello or deleting a conversation, you can also disable Firefox Hello:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - In the about:config page, search for the preference loop.enabled.
- Observe the Value column of the loop.enabled row.
- If it is set to false then do nothing.
- If it is set to true, double-click on it to set it to false.
Mozilla content
Tiles
When you open a new tab in Firefox, you see several tiles that link to different websites. For new users, the New Tab Page in Firefox provides recommendations including both referrals to sponsored partner sites and content we consider important to our mission ("Directory Tiles"). For existing users Firefox will display visited sites, as well as suggested and sponsored content based on the user’s browsing history.
Directory Tiles and suggested sites will establish a connection to download content and the thumbnails to be shown in the New Tab Page. In order to disable the display of such sites, refer to New Tab page in Firefox.
Disabling the display of such sites won't stop the feature from communicating with Mozilla's servers though. In order to change that:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - In the about:config page, search for the preferences browser.newtabpage.directory.ping and browser.newtabpage.directory.source.
- Double-click on those preferences and set them to a blank string.
Snippets
If you use the built-in default homepage about:home, Firefox will show some Mozilla related content around the search box ("Snippets"), which is updated once a day. If you'd like to disable connections to Mozilla's snippets server:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - In the about:config page, search for the preference browser.aboutHomeSnippets.updateUrl.
- Double-click on it and set its value to a blank string.
Geolocation for default search engine
In order to set the right default search engine for your location, Firefox will perform a geolocation lookup once by contacting Mozilla's servers and store the country-level result locally. This connection happens on the first start of Firefox - in case you want to prohibit that, you will have to preconfigure the browser and set the browser.search.geoip.url preference to a blank string.
"What's new" page
After a browser update, Firefox might show an additional tab next to your usual homepage to offer more information on changes or new features included in the update. To disable this page from being shown:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - In the about:config page, search for the preference browser.startup.homepage_override.mstone.
- Double-click on it and set its value to ignore.
Add-on metadata updating
The Add-ons manager displays information about each add-on you have installed and provides personalized recommendations in the Get Add-ons pane. To keep this data updated, Firefox will request information from the Mozilla Add-ons gallery once a day (for more information, see this blog post). To disable these updates:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - In the about:config page, search for the preference extensions.getAddons.cache.enabled.
- Observe the Value column of the extensions.getAddons.cache.enabled row.
- If it is set to false then do nothing.
- If it is set to true, double-click on it to set it to false.
Diagnostics
Firefox can submit certain diagnostics data including Telemetry, Firefox Health Report and Crash Reports data to Mozilla to provide information that helps improving the browser. In order to disable the sharing of this data, refer to Data Choices Tab.
Media capabilities
OpenH264 codec
Firefox will make use of the OpenH264 codec provided by Cisco in order to support the H.264 video codec in WebRTC, a technology allowing for peer-to-peer video communication on the web, like in Firefox Hello. For more information about this, see the OpenH264 Now in Firefox blog post. The OpenH264 codec is not distributed with Firefox but gets downloaded at the first start of Firefox. In case you want to prohibit that, you will have to preconfigure the browser and set the media.gmp-gmpopenh264.autoupdatemedia.gmp-gmpopenh264.enabled preference to false.
WebRTC
WebRTC (Web Real-Time Communication) is a technology which provides direct browser-to-browser communication (audio, video, filesharing). As it is drafted and implemented at the moment, WebRTC can lead to your local IP address being exposed to websites even when you are behind a VPN or a NAT router - in the WebRTC API this data would be used to set up a peer-to-peer connection between two clients. There is discussion about if and how this should be adressed at the moment. If you would like to disable WebRTC:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - In the about:config page, search for the preference media.peerconnection.enabled.
- Observe the Value column of the media.peerconnection.enabled row.
- If it is set to false then do nothing.
- If it is set to true, double-click on it to set it to false.
Send Video To Device
Firefox contains a "Send Video To Device" feature to send HTML5 video content to a Roku, Chromecast or similar device in the same network. In order to discover and pair with such a device, Firefox will send SSDP packages (Simple Service Discovery Protocol, multicast address 239.255.255.250, port 1900) to the local network which can trigger a firewall dialog asking you if you want to allow such connections. A setting to control this behaviour will be available in an upcoming version of Firefox.To disable this feature:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page. - In the about:config page, search for the preference browser.casting.enabled.
- Observe the Value column of the browser.casting.enabled row.
- If it is set to false then do nothing.
- If it is set to true, double-click on it to set it to false.
Malware
If your computer is infected with a virus, trojan, spyware, or other malicious software, then Firefox's Internet connection may be being piggybacked in order for the malware to communicate with its author or to deliver advertisements, etc. If you suspect this is the case, consider seeking advice from a forum specializing in malware removal. For more information, see Troubleshoot Firefox issues caused by malware.
Loopback connection
A loopback connection (to IP address 127.0.0.1) can be made by Firefox on non-Unix machines. In this case the browser is communicating with itself as expected, and it is not recommended that this communication be blocked. See bug 100154 for more information.
Based on information from Connections established on startup - Firefox (mozillaZine KB)