DNS Routing Failure

[#1]

Hi,
I've been having problems resolving web names and it looks as thought the problem is because the automatic resolution of the DNS is to 212.159.6.9 then 212.159.6.10.  When I have this default setup I cannot browse the web (connecting directly to IP works fine, so games and such seem ok), however if I switch them around it works fine.
Is there a problem with 212.159.6.9 that needs resolved?
Cheers,
Yarek

[#2]

It has been suggested elsewhere in the forums that using one Plusnet address and one OpenDNS address such as 208.67.222.222 is advisable.
If one source goes down the other is available as a backup.

[#3]

The idea of using one Plusnet DNS address and one OpenDNS address does not say much for the reliability of the Plusnet DNS servers.  And isn't the point of having two DNS servers so that if one fails the other takes over?  Yarek's experience implies that 212.159.6.9 was not responding but 212.159.6.10 did not take over, although it was working.

[#4]

Quote from: ReedRichards

The idea of using one Plusnet DNS address and one OpenDNS address does not say much for the reliability of the Plusnet DNS servers.

...or, as one could extrapolate, OpenDNS servers. I think the idea was to put as much 'distance' between the two options as possible.
It was just a thought though

[#5]

Out of interest, is your computer set to resolve using those IPs or is it set to use your Routers IP address as it's DNS server?

[#6]

Quote from: Yarek

Is there a problem with 212.159.6.9 that needs resolved?

Not as far as I'm aware. TBH, the IP address you use does not determine the site that your DNS requests will be routed to. They'll always be routed to the closest site to the edge router you're connected to (although there are multiple servers at each site).
If you have the problem again then open a command prompt and perform a lookup against each of the caching server addresses you're using.

C:\Users\Bobby>nslookup bbc.co.uk 212.159.6.9
Server:  ptn-cdns01.plus.net
Address:  212.159.6.9
Non-authoritative answer:
Name:    bbc.co.uk
Address:  212.58.224.138

C:\Users\Bobby>nslookup bbc.co.uk 212.159.6.10
Server:  ptn-cdns02.plus.net
Address:  212.159.6.10
Non-authoritative answer:
Name:    bbc.co.uk
Address:  212.58.224.138

If you get a result like the one above then that suggests that DNS resolution is working as it should be.

Quote from: ReedRichards

The idea of using one Plusnet DNS address and one OpenDNS address does not say much for the reliability of the Plusnet DNS servers.

There's certainly no harm in adopting a bit of redundancy. It's also useful if you use your machine for roaming because you'll not be able to connect to the Plusnet caches from a non-Plusnet connection.

[#7]

Quote from: Bob

Not as far as I'm aware. TBH, the IP address you use does not determine the site that your DNS requests will be routed to. They'll always be routed to the closest site to the edge router you're connected to (although there are multiple servers at each site).

Bob - are you saying in effect that it is a waste of time entering DNS, whether they be PN or OpenDNS, as they won't be used anyway?

[#8]

No - he's saying that the Plusnet DNS server IP address is not actually a server address, its the address of a load balancer, which will send your request to the actual servers which are at the site closest to the edge router that your internet connection presents onto the PN network.
So, PN when you see the 212.159.6.9 and 212.159.6.10 addresses, this is not two servers, but two load balancers, which each share the load amongst multiple servers.

[#9]

Does that mean that regardless which Plusnet DNS load balancer is specified as primary and secondary they could both point to the same server closest to the edge router so if that is dodgy you aren't going to get anywhere so the supposed primary and secondary servers are a waste of time
Or have I totally misunderstood the answer

[#10]

Why does everything with PlusNet have to be so complicated?

[#11]

we'd all be bored if it wasn't...

[#12]

....but maybe there wouldn't be so many problems?
adie:quote

[#13]

Quote from: Oldjim

Or have I totally misunderstood the answer

If you have then so have I as it read it in exactly the same way.

[#14]

I read it the same way too

[#15]

Well - my previous solution seemed to work - for a while.  The load balancing thing certainly suggests where my problem is today though - it doesn't work regardless of the DNS order.
Today, it's completely borked and I';m not able to browse at all (can connect to direct IP addresses again though) and my work PC using work DNS is working (that's what I'm using to type this btw!).
When I try the above nslookup bbc.co.uk <dns IP> it completely fails (times out) with 212.158.6.10 but resolves as above with 212.158.6.9 (isn't this the other way around from before?  oh well).
I'll try the opendns as a temporary measure and see if that resolves my problem in the meantime.  Please try and fix the issues as there's clearly something not working with the DNS currently.