Auto DNS stopped working - best DNS addresses to use?

[#1]

Weird thing is happening. I was finding the Apple site troublesome. iTunes was slowing to a crawl and timing out on me and I couldn't access tutorial videos on the website. After asking around it seemed others didn't have problems. I have found a fix via Think Broadband. I need to enter DNS addresses manually in my computer's network settings. Its been on Auto up until now. Manual mode fixes everything for me now though.
I've found four DNS addresses on the Kitz website for plusnet:
212.159.13.49
212.159.13.50
212.159.6.9
212.159.6.10
Should I use all of these or just one or doesn't it matter?
anyone know why the auto mode has suddenly stopped working? Its been fine for years. Is it something I should worry about ?

[#2]

Hi there,
Any of those should be okay.  However we quote 49 & 50 on our website.
http://portal.plus.net/support/customer_service/using/settings.shtml
Do you know which servers your router is using?

[#3]

That was quick! thanks.
My router looks like its using 0.0.0.0 (sic - ?). I guess this is some auto mode too eh? Can the router get the dns addresses automatically somehow?
I was wondering if the problem was with plusnet dns (which I assumed I was using) but entering PN addresses seemed to fix my probs so I'm assuming the issue lies at my side.
I used to "get" all this sort of thing - but now I've gone all vague. I hope its not age.

[#4]

It sounds like your router isn't picking up our DNS server and thus your PC isn't getting them either.
I reckon both problems would be solved by manually specifying them on your router.  As to why it's happened is another question!

[#5]

I tend to use one of the four you've quoted and one of OpenDNS's server addresses. That way you have a backup if our servers ever do go up the spout (also helps if you're roaming using a laptop).

[#6]

Bob, I'm off on a tangent (maybe), but could you explain (or point me to a link) on how/when one's router auto picks up the DNS addresses and how/when/how often they get refreshed?
Many Thanks,
Chris.

[#7]

Quote from: Jameseh

Hi there, Any of those should be okay.  However we quote 49 & 50 on our website.

The portal may quote these but PN DHCP server always issue the other 2. i.e.
212.159.6.9
212.159.6.10

[#8]

Quote from: Anotherone

Bob, I'm off on a tangent (maybe), but could you explain (or point me to a link) on how/when one's router auto picks up the DNS addresses and how/when/how often they get refreshed? Many Thanks, Chris.

Believe this is dependent on the lease time of the router. My router is working on 5 minute lease time which probably have been issued by my ethernet modem. As the ethernet modem does not seem to use DNS I'm assuming that when the router/modem renew the lease the modem pass over the IP address but the DNS addresses are being requested from PN DHCP server.