Omar Evans

I can confirm that it affects Macs.

In MC-15525, Grum indicates that Mojang made the decision to set java.net.preferIPv4Stack to true (java.net.preferIPv6Addresses is false by default). According to the Java documentation, setting java.net.preferIPv4Stack to true completely prohibits the use of IPv6. This decision will have to be reversed (or at least an IPv6 non-disabled client needs to be made available) in order to fix this issue (I hereby confirm it still exists in 1.7.9—java.net.SocketException: protocol family unavailable—, and that the presence of IPv6 internet, which I have, is irrelevant).

Torabi, according to the Java documentation, setting java.net.preferIPv4Stack to true as MC-3776 indicates disables IPv6 entirely. I don't think that setting java.net.preferIPv6Addresses, which is the property referenced here, to false actually affects anything, as that appears to be the default. In any case, the decision Grum made over a year ago is must be reversed to fix any issue involved with IPv6. This will not be an issue experienced by the minority for much longer, if it even is a minority issue right now (the uptick in the number of comments on this issue in the past few days might be a hint).

I've noticed that there are also no AAAA records for mojang.com and minecraft.net. Does Mojang even have IPv6 in their office? If not, then maybe they need to arrange to get it, otherwise, how can anyone be sure that the errors were due to customers "broken IPv6", as Grum stated.

Unfortunately, by disabling IPv6 for minecraft, SRV records simply don't work for people with a functioning IPv6 stack, which is starting to become significant due to ISPs like Comcast rolling it out for all their customers. It's unfortunate that some people have broken stacks, but it unacceptable that your "fix" breaks things for people who suddenly gain a functioning one.