Why is IPv6 disabled for rootless/slirp4netns containers?

[rugk]

The man page says:

enable_ipv6=true|false: Enable IPv6. Default is false. (Required for outbound_addr6).

I interpret that as such, that IPv6 is disabled by default and thus containers/ports bound can only be reached via IPv4. Is that true?

If so, why is that so? Given various initiatives to finally get to the day we use IPv6 only, I wonder why you do not enable this by default…?

[AkihiroSuda]

Probably safe to enable v6 by default, but not massively tested as v4 and there might be some vulns

[rhatdan]

This should probably be done in containers.conf then. That way users could have a way to customize.

[Luap99]

You can already set this in containers.conf with network_cmd_options = ["enable_ipv6=true"]

@AkihiroSuda How does slirp4netns behave when ipv6 is disabled in the kernel, will it fail or ignore the ipv6 setup?

[AkihiroSuda]

@AkihiroSuda How does slirp4netns behave when ipv6 is disabled in the kernel, will it fail or ignore the ipv6 setup?

Haven't tried

[github-actions]

A friendly reminder that this issue had no activity for 30 days.

[rhatdan]

@rugk interested in opening a PR containers/common to change the default?

[rugk]

Hmm, tried with containers/common#741, though I have no idea whether that is the correct thing to change… 😄

Feel free to change it by yourself, you likely better know what exactly to change.

[rhatdan]

You need to change default.go, we will carry on the conversation in the PR.