[ubuntu-uk] DNS - request for info/advice

[Mac]

I should start by saying I don't know much about DNS and how it works. 
So I wonder if any of you knowledgeable folks have the time to enlighten 
me about something I just discovered.

I was reading about the patch to DNS that's just been released (and my 
Ubuntu systems picked up the updates today).  And I thought I'd check 
the security of the DNS I use (or believed I did!) via the tool on Dan 
Kaminsky's site at http://www.doxpara.com/

When I did this, I discovered (a) that the DNS I was using hadn't been 
patched, and (b) that it was not the server I thought I was using!

You see, I assumed I was using my ISP's DNS server, because that was 
entered in my router settings.  But it seems that is overridden by the 
one in /etc/resolv.conf, presumably the NetworkManager default:

213.130.128.32
213.130.128.33

And a bit of dig-ging (pardon the pun) and investigation revealed that 
this was also the default on my Debian Etch box and laptop.

So, am I right in thinking that NetworkManager sets this default DNS? 
(It seems to be operated by a firm in Manchester - anything to do with 
you, Tony?! ;-)  )

How come it overrides the router setting?

And how come there's no indication that the install process will decide 
a DNS server without asking (especially one that seems not to have been 
patched, which makes one worry a bit about how well-maintained it is)?

TIA

Mac