Bloody Optus DNS

To make a domain work, the DNS server has to be under the control of the domain controller. Windows domains use all sorts of magic host names and records to find stuff.

The initial router I was supplied by Optus (a Cisco unit) allowed me to specify the DNS IP addresses handed out by the built-in DHCP server so all was good - the primary DNS was the domain controller and the secondary was Optus' own.

The router was fast enough but it would occasionally reset at random times (less random when it was hot). One day it gave up entirely. Optus were good in that they sent somebody out pretty much straight away, replaced the router and I was back up and running.

They replaced it with a Netgear unit which also seems pretty fast but it doesn't allow me to specify the DNS! So after some head scratching I decided to try running DHCP on my DC. I've had problems with this before as for whatever reason the switch will not pass on the broadcasts and I found this problem to be worse on wireless.

Anyway I've configured the DHCP server and this has been going Ok.

In the past I found the routers would act as DNS proxies so you would configure the DC as the primary DNS and the router as the secondary. This router doesn't do this and just passes the IP of the DNS it has been given out to the DHCP clients on the network. I didn't realize this and configured the router as the secondary so the effect was that lookups worked as the DNS server would forward up to the network but then if the DC was down (say because I shut it down over night) DNS wouldn't work. I figured this out recently and configured this correctly so even if the DC is down, so long as the computer has a cached IP from a previous DHCP it works.

The problem then is that if you try and access an address that isn't in the DNS the stupid Optus DNS redirects you to this true local search provider. This meant that lookups for my local servers by name often resolved to true local! This is pretty frustrating and not helpful.

Turns out there is an Optus resolver that doesn't do this. This guy posted details of the IP addresses thankfully and this seems to work.

http://justlocal.blogspot.com.au/2009/11/annoying-optus-dns-assist-feature.html

So life is good. If only I could get my VMs to auto-boot with the box...