'''Yes, Firefox does support IPv6'''. Firefox, like most modern web browsers, has been designed to support the transition from IPv4 to IPv6. If your internet service provides IPv6 connectivity and your network infrastructure supports it, Firefox will automatically use IPv6 if a website is also available over IPv6. Websites that are configured to support IPv6 will be accessed using IPv6 by default in Firefox if your network is configured for it. When both IPv4 and IPv6 are available, the browser may prioritize the use of IPv6, provided your network and the website's server are configured to support it. You can check whether Firefox is using IPv6 to connect to a website by visiting an IPv6-specific test site or using network diagnostic tools that can provide information about the protocol being used for the connection.