IPv6 and commit d882add695bbd5ea03961c08ac2c0380fbf2947b

[Jeremy Allison]

On Tue, Sep 20, 2022 at 10:53:04PM -0400, Nathaniel W. Turner wrote:
>   Hi Jeremy,
>     On Fri, Sep 16, 2022 at 01:33:26PM -0700, Jeremy Allison via
>     This is internal to discover_dc_dns(), so you
>     could probably add an extra flag here to tell
>     discover_dc_dns() to return IPv6-only, and
>     have it skip that DC if it doesn't have an
>     IPv6 address returned.
>
>   Thanks for taking a look at this! I'll work on a patch. 
>   What's the right behavior here? In the case where the local server has no
>   routable IPv6 addresses (e.g. link local IPv6 addresses only), we might
>   infer that we're only interested in IPv4 addresses for the DC, and vice
>   versa.
>   If we don't have easy access to the set of local addresses in this code
>   path, a simpler alternative might be to pick up to 1 IPv4 address and up
>   to 1 IPv6 address, and potentially try them both. If the test connection
>   fails quickly in the case of an unusable address, this might be OK.
>   Thoughts?

Change the API for dsgetdcname() so the caller
can specify if they want IPv6 or IPv4. Don't
return more than one address - we don't want
to double the lookup time for a down-DC.

process_dc_dns() should really be changed
to do ads_cldap_netlogon() pings in parallel
for every address given to it.