dns free ipv6 bootstrap nodes?

[sixcorners]

Checklist

• My issue is specific & actionable.
• I am not suggesting a protocol enhancement.
• I have searched on the issue tracker for my issue.

Description

ipv6 bootstrap nodes were added in #3523 and then were removed in f455264. Could bootstrap.libp2p.io be made to work over ipv6 and/or could the mars.i.ipfs.io entry get it's ipv6 added? Or is the ipv6 address for that node not a good thing to rely on?

[sixcorners]

I don't exactly know what happened but I looked at what bootstrap.libp2p.io pointed at and manually connected to a peer with ipfs swarm connect /ip6/2604:1380:2000:7a00::1/udp/4001/quic/p2p/QmbLHAnMoJPWSCR5Zhtx6BHJX9KiKNN6tpvbUcqanj75Nb. I guess it should have worked with the current configuration but it didn't. Before I manually connected it was saying I had no peers. Weird.

[Jorropo]

There already IPv6 addresses are accessible through the dnsaddr resolution.

[sixcorners]

FYI. I brought up a node on a vm with no ipv4 internet connection and go-ipfs failed to connect to peers. The VM had an private ipv4 and an ipv4 vpn. Maybe that messed something up.

Anyway. That's why I originally created this ticket. I guess I should try to find a way to reproduce it and make another ticket. I think it's fine to make this ticket just about the inclusion of dns free ipv6 bootstrap nodes. Thanks.

[Jorropo]

@sixcorners I think your VM DNS resolvers was probably broken.