Firefox Ipv6

• Firefox Disable Ipv6
• Ipv6 Url

If you have a problem connecting to a website, you may see error messages like Server Not Found. This article describes how to troubleshoot problems that cause this error.

Firefox Developer Edition. Get the Firefox browser built just for developers. Check out the home for web developer resources. Firefox Reality. Explore the web with the Firefox browser for virtual reality. Donate your voice so the future of the web can hear everyone. Firefox supports IPv6 by default, which may cause connection problems on certain systems. To disable IPv6 in Firefox: Type about:config in the address bar and press Enter Return. A warning page may appear. Click I accept the risk! Accept the Risk and Continue to go to the about:config page. In the Search field, enter network.dns.disableIPv6.

• For troubleshooting other error messages, see Error loading websites.

Table of Contents

• 3Firefox cannot load websites but other browsers can
• 4Firefox cannot load certain websites

To begin, try opening a website in another browser (such as Internet ExplorerSafariEpiphany or Chromium).

• If all other browsers cannot load the website, move on to the No browsers can load websites section.
• If the other browsers can load the website, skip ahead to the Firefox cannot load websites but other browsers can section.

If neither Firefox nor your other browser can load websites, your problem is not in Firefox so you should seek help elsewhere.Apple support includes these articles:Microsoft support includes these articles:

• (OS X 10.8 Mountain Lion): If you can't connect to the Internet

• (OS X 10.9 Mavericks): Solve problems with connecting to the Internet

• (OS X 10.10 Yosemite): Solve problems connecting to the Internet

• (OS X 10.11 El Capitan): Solve problems connecting to the Internet

• (OS X 10.12 Sierra): Troubleshoot connecting to the Internet

• (Windows 10): Why can't I get online? and Fix network connection issues in Windows 10
• (Windows 8): Why can’t I get connected?
• (Windows 7): Why can’t I get connected?
• (Windows Vista): How to troubleshoot network connectivity problems in Internet Explorer
• (Windows XP): How to troubleshoot home networking in Windows XP

You should also check the following:You should begin by checking the following:

• Make sure your modem and/or router are both on and are not indicating errors.
• If you are using a wireless connection, make sure that you are connected to the right access point.
• Make sure your Internet security software (including firewalls, antivirus programs, anti-spyware programs, and more) is not blocking connections to the Internet. For instructions on how to configure these programs, see the Configure firewalls so that Firefox can access the Internet article.
• If you use a proxy server, make sure that the proxy server can connect to the Internet. For instructions on configuring proxy settings in Firefox, see Firefox connection settings below.

If Firefox cannot load websites, but your other browser can, follow the instructions below.

Cannot load websites after updating Firefox

If you were able to load websites until you updated Firefox, your Internet security software (including firewalls, antivirus programs, anti-spyware programs, and more) is likely preventing Firefox from connecting to the Internet. Some Internet security programs can block Internet access even when they are in a 'disabled' state.

In general, you should remove Firefox from your program's list of trusted or recognized programs, then add it back. For instructions on how to configure these programs, see the Configure firewalls so that Firefox can access the Internet article.

Firefox connection settings

If you connect to the Internet through a proxy server that is having connection problems, you will not be able to load websites. To check your connection settings in Firefox:

1. In the Menu bar at the top of the screen, click Firefox and select Preferences.Click the menu button and select ...
2. Select the General panel.
3. Scroll down to Network Proxy and click .
4. Change your proxy settings:
   • If you don't connect to the Internet through a proxy (or don't know whether you connect through a proxy), select No Proxy.
   • If you connect to the Internet through a proxy, compare Firefox's settings to another browser's (such as Internet Explorer - see Microsoft's guide to proxy settings) (such as Safari - see Safari for Mac: Set up a proxy server with Safari).
5. Click to close the Connection Settings window.
6. Close the about:preferences page. Any changes you've made will automatically be saved.

1. In the Menu bar at the top of the screen, click Firefox and select Preferences.Click the menu button and select ...
2. Select the Advanced panel.
3. Select the Network tab.
4. In the Connection section, click .
5. Change your proxy settings:
   • If you don't connect to the Internet through a proxy (or don't know whether you connect through a proxy), select No Proxy.
   • If you connect to the Internet through a proxy, compare Firefox's settings to another browser's (such as Internet Explorer - see Microsoft's guide to proxy settings) (such as Safari - see Safari for Mac: Set up a proxy server with Safari).
6. Click to close the Connection Settings window.
7. Close the about:preferences page. Any changes you've made will automatically be saved.

DNS Prefetching

DNS Prefetching is a technique Firefox uses to speed up loading new websites. To disable DNS Prefetching:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. Right-clickHold down the control key while you click in the list of preferences, select New, and then select Boolean.
3. In the Enter the preference name field, enter network.dns.disablePrefetch and click .
4. Select true when prompted to set the value and click .

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. In the Search field at the top of the page, enter network.dns.disablePrefetch.
3. If the preference does not already exist, select Boolean and click the Add button to create the preference.
4. Change the preference value from false to true by pressing the Toggle button.

IPv6

Firefox supports IPv6 by default, which may cause connection problems on certain systems. To disable IPv6 in Firefox:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. In the Search field, enter network.dns.disableIPv6
3. In the list of preferences, double-clickclick the Toggle button next tonetwork.dns.disableIPv6 to change its value from false to true.

If you find that Firefox can load some websites but not others, first clear your Firefox cookies and cache:

1. Click on the menu button to open the menu panel.Click the Library button on your toolbar. (If you don't see it there, click the menu button then click Library.)
2. Click History and select Clear Recent History….
3. In the Time Range to clear: drop-down, select Everything.
4. Below the drop-down menu, select both Cookies and Cache. Make sure other items you want to keep are not selected.
5. Click .

Check for malware

If clearing your cookies and cache did not enable you to load the websites that did not work in Firefox, you should check your computer for malware. Certain types of malware are known to target Firefox and can prevent it from loading various websites:

• If you have an antivirus or Internet security program, update its detections database and do a full scan of your system.
• If you still have problems, see How do I get rid of malware?.

Based on information from Error loading websites (mozillaZine KB)

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

• 1Automatic updates and Security
• 2Prefetching
• 3User-invoked content
• 4Mozilla content
• 6Media capabilities

Auto-update checking

Firefox occasionally checks to see if any updates are available for itself and for your search engines. The ability to disable Firefox update checking was removed in Firefox 63. Advanced users and IT administrators can use a policy to disable Firefox update checks. See Managing Firefox Updates.

Firefox also checks to see if any updates are available for your add-ons (extensions, themes). To disable this check:

1. Click the menu button , click Add-ons and Themes Add-ons and Themes Add-ons and select Extensions.
2. 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:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. In the about:config page, search for the preference extensions.blocklist.enabled.
3. 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 and malware protection lists updating

Phishing, unwanted software and malware protection lists may be updating. To turn this off:

1. In the Menu bar at the top of the screen, click Firefox and select Preferences.Click the menu button and select ...
2. Select the Privacy & Security panel.
3. Uncheck Block dangerous and deceptive content.

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:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. In the about:config page, search for the preference browser.safebrowsing.downloads.remote.enabled.
3. Observe the Value Column of the browser.safebrowsing.downloads.remote.enabled row.
   • If it is set to false then do nothing.
   • If it is set to true then double-click on it to set it to false.

Tracking protection list updating

The tracking protection list may be updating itself. To turn this off:

1. In the Menu bar at the top of the screen, click Firefox and select Preferences.Click the menu button and select ...
2. Select thePrivacy & Security panel.
3. Under Content Blocking, choose the Custom setting.
4. Uncheck Trackers.

The tracking protection list may be updating itself. To turn this off:

1. In the Menu bar at the top of the screen, click Firefox and select Preferences.Click the menu button and select ...
2. Select the Privacy & Security panel.
3. Under Enhanced Tracking Protection, choose the Custom setting.
4. Uncheck Tracking content.

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 named OCSP to confirm that the certificate is still valid. To turn this off:

1. In the Menu bar at the top of the screen, click Firefox and select Preferences.Click the menu button and select ...
2. Select the Privacy & Security panel.
3. In the Security section under Certificates, uncheck Query OCSP responder servers to confirm the current validity of certificates.

Login breach information

Firefox Monitor warns you if your online accounts were involved in a known data breach.
For more information, see Firefox Lockwise - Alerts for breached websites.

To get the latest login breach information and more, Firefox connects to firefox.settings.services.mozilla.com

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:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. In the about:config page, search for the preference network.prefetch-next.
3. 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:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. In the about:config page, search for the preference network.dns.disablePrefetch.
3. 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:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. In the about:config page, search for the preference network.http.speculative-parallel-limit.
3. 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 Get Add-ons pane. This connection is not made if the add-ons manager is not opened.

Home page loading

Your home page may be loading. To change your home page to something that doesn't generate connections to the Internet:

1. In the Menu bar at the top of the screen, click Firefox and select Preferences.Click the menu button and select ...
2. Select the General panel.
3. 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 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:

1. Click the menu button , click Add-ons and Themes Add-ons and Themes Add-ons and select Extensions.
2. 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.

Downloads restarted

When you start Firefox, any interrupted downloads from your previous browsing session may be automatically resumed.

1. Press Ctrl + JCtrl + Shift + Ycommand + J to open the Downloads window.
2. 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 type of information to sync on Firefox? article.

Contextual feature recommendations and other notifications

Firefox may make feature recommendations specific to a type of website you're on or relevant to a current task. You can disable connections by setting browser.newtabpage.activity-stream.feeds.asrouterfeed to false.

Experiments or studies

• To disable new feature experiments, set messaging-system.rsexperimentloader.enabled to false.
• To disable the running of experiments, set app.normandy.optoutstudies.enabled to false. This is not necessary if app.normandy.enable is also set to false.
• To disable studies, feature rollouts and emergency hotfixes related to Normandy, set app.normandy.enabled to false.

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:

Firefox Disable Ipv6

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. In the about:config page, search for the preference browser.aboutHomeSnippets.updateUrl.
3. 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:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. In the about:config page, search for the preference browser.startup.homepage_override.mstone.
3. 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 panel. 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:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. In the about:config page, search for the preference extensions.getAddons.cache.enabled.
3. 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.

Firefox can submit certain diagnostics data, including Telemetry and Crash Reports data to Mozilla, to provide information that helps improve the browser. You can disable sharing of this data in Firefox OptionsPreferencesSettingsPreferences. To disable the sharing of this data:

1. In the Menu bar at the top of the screen, click Firefox and select Preferences.Click the menu button and select ...
2. Select the Privacy & Security panel.
3. Uncheck the boxes under the section, Firefox Data Collection and Use.

In addition, Mozilla will ask a small sample of users to rate their experience with Firefox to get a better insight into the sentiment about the browser. For more information about this see https://wiki.mozilla.org/Advocacy/heartbeat. The rating feature will establish a connection to Mozilla's servers at startup, which you can turn off like this:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. Find the preference app.normandy.enabled.
3. Set the preference value to false by double clicking on it.

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. 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.enabled preference to false.

DRM content

To disable this feature, see Watch DRM content on Firefox.

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 local clients.

For different methods and granular controls on how to mitigate this issue, see Media/WebRTC/Privacy Mozilla Wiki page.

Ipv6 Url

Send Video To Device

Firefox contains a 'Send Video To Device' feature that is disabled by default, to send HTML5 video content to a Roku, Chromecast or similar device in the same network. When this feature is enabled, Firefox will send SSDP packages (Simple Service Discovery Protocol, multicast address 239.255.255.250, port 1900) to the local network, to discover and pair with such a device. This can trigger a firewall dialog asking you if you want to allow such connections.

To disable this feature:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. In the about:config page, search for the preference browser.casting.enabled.
3. 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.

Firefox's captive portal feature tests whether your network connection requires logging in, for example, on a public wi-fi hotspot, by regularly connecting to http://detectportal.firefox.com/success.txt. Firefox will also make connections to this URL to check if your current network supports IPv6.

To disable this feature:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click to go to the about:config page.
2. In the about:config page, search for the preference network.captive-portal-service.enabled (for example, you can type portal in the search box above the list and pause while the list is filtered).
3. Observe the Value column of the network.captive-portal-service.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.
4. In the about:config page, search for the preference network.connectivity-service.enabled (for example, you can type connectivity in the search box above the list and pause while the list is filtered).
5. Observe the Value column of the network.connectivity-service.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.

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.

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)