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Firefox prefers IPv4 address in a dual-stack environment
Hi, I'm using IPv4 as well as IPv6 addresses in my home network. But Firefox uses always the IPv4 connection when I open a website. When I open the same website in MS Ed… (Lesen Sie mehr)
Hi,
I'm using IPv4 as well as IPv6 addresses in my home network. But Firefox uses always the IPv4 connection when I open a website. When I open the same website in MS Edge, the IPv6 connection is used.
I've captured the network traffic during opening a website in Firefox, which is reachable over IPv4 and IPv6. First I see two DNS queries (A and AAAA) for the domain name. Both responses containing the correct IP address, and they arrive nearly at the same time at the client. Next I can see the TCP handshake. But it's send between the IPv4 address only. No IPv6 connection was attempted.
When I run the IPv6 test at https://test-ipv6.com, the IPv6 resuls are nearly fine. Only the web browser test says "Your browser has real working IPv6 address - but is avoiding using it."
When I run the same test in MS Edge, all tests are fine.
So it seems that this is not a OS or network issue. It affects Firefox only.
What I've already tried:
- Disabled all extensions
- Created a new profile
- Used the IPv6 address of the website instead of the FQDN -> Works fine.
- Checked DNS cache of Firefox (about:networking). It contains the IPv4 and IPv6 addresses of the requested websites
I guess that Firefox prefers the A record for some reason. But I've no idea why. Has anybody an idea what could causing this?
Thanks.
Jas Man