Alternate secondary DNS

Amahi has a way to set an alternate DNS provider for the secondary DNS to be OpenDNS. It can be done with setting this value en /etc/hdactl.conf (though this is not well tested prior to Amahi 7):

  $use_opendns_secondary = 1;

This is not a good idea unless you know what you are doing. This is hard to expose on the dashboard area. It's hard to understand for the average user and it misbehaves under current windows clients.

Modern windows clients alternate queries between the primary and secondary over the course of minutes or less. This was not meant to be like that, but Microsoft did implement that (we believe starting in Vista).

Now, the intent of the secondary DNS server was for when the primary did not work, i.e. as a fallback (hence the name).

If this is done, queries to http://hda/ and any apps will not work some percent of the time and some queries will be taken to OpenDNS fallback. Not only that, the DNS cache in the client will make it not work well if that fallback from opendns is cached.