The idiot's guide to dealing with DNS failure

[#1]

A couple of weeks ago our Plusnet connection failed for the first time in many years. I have since learned that this was a national outage which included Northern Ireland, and my screen displayed Cannect connect to DNS Server.

Like any non-techie I hadn’t a clue what this meant, though I see PN’s DNS mentioned fairly frequently on this forum. We tried the Plusnet site via mobile data but could find nothing, so when our connection was restored later that night I decided to avoid a recurrence. I’m sorry to see that Plusnet isn’t interested, as there has been no announcement since the fault other than a scattering of random posts across a couple of threads.

Here’s an idiot’s guide to what I discovered -- no doubt the experts can provide more detail but all we simple folk want is to restore our service. Basically the DNS server is a glorified and immense phone book between me and the IP address which every user is allocated. When too many people come on the ‘line’ the system becomes overloaded and can’t cope though I’ve no idea whether this caused the recent widespread failure.

Top of the selection from Duckduckgo was Cloudflare which offers a free DNS server with various features -- I found it here 

I would never have found the DNS settings without the Cloudflare guide, but even I took only three minutes to set them up so it has to be dead easy! So far the app works perfectly and is noticeably faster than the PN DNS though I have printed out their instructions and keep them handy. Other servers are available I suppose.

[#2]

Few things worth noting...

• The Plusnet Hub One does not allow you to change the DNS servers it uses for client/hub resolution (you would need to either configure directly on connected clients or use some other third party solution). The Plusnet Hub Two does allow DNS to be specified for client resolution.
  
  
• If you use non-Plusnet DNS servers, then the Plusnet Safeguard parental controls service will not work (if you are dependent on it).
  
  
• In principal you will get better response times from the Plusnet DNS servers (although in practice, this probably won't be perceptible to the human eye).

[#3]

@Longliner 

Bearing in mind what Bob said above, you might be interested in DNS Benchmark at https://www.grc.com/intro.htm - Freeware/Utilities/DNS Benchmark

[#4]

Moderators Note

This topic has been moved from Broadband to Everything Else

[#5]

@RobPN that DNS benchmark is interesting. I've always used the OpenDNS servers and currently have them configured as the upstream DNS servers to the internal router DNS, with that being supplied to clients via DHCP.

NB this is not a Hub2 BTW

I'd always assumed that using the internal server on the router, with its cache, would be quicker than going direct to the upstream ones.

The benchmark results showed that PN's servers were slightly faster than OpenDNS and that both were on average in fact faster than the routers internal server. We're only talking 6 hundreths though!. Maybe I'll change my router config to supply the external servers directly via DHCP , maybe one of the PN ones and an OpenDNS.

[#6]

@MisterW 

It's been quite a while since I last used DNS Benchmark but I ran it again a couple of times after posting the link.

ICBW, but like you, I was surprised to see the PN servers featuring so high in the 'fastest' list as I'm pretty sure that didn't used to be the case.  Weren't the PN DNS servers reconfigured recently?  If so that might have some bearing on the 'perceived' difference.

Years ago I used to have the secondary DNS in my router set to one of the PN addresses but nowadays I'm using OpenDNS and Cloudfare in that order because ISTR they came out as the fastest some time ago when I chose them.  I have occasionally used a PN DNS when checking something and became a victim of the recent failure after I'd forgotten to change the settings back on a PC (but quickly realised what the problem was).

[#7]

Weren't the PN DNS servers reconfigured recently?

They were.

[#8]

Thanks very much everyone, interesting but you  all miss my point. Like perhaps a million PN customers I have no interest in the tech subtleties, all we want is for the darn thing to work. Doubly so when a couple of our community group have been pushed into this BB phone system and no BB, no phone which isn't funny when you're in your 80s.

For the same reason I am sorry that the mods have dumped all posts relating to this outage in the Everything Else thread. If a national outage isn't worth prominence on the BB thread I don't know what is especially as I see DNS frequently mentioned in this forum. I think the least PN could do is to update its service page for such events. Maybe this forum (which I stress I find very helpful) is aimed more at the enthusiast than the everyday user. Meantime I keep the cloudflare instructions handy.

Back to reality for me, which is my beautifully made Honda lawnmower engine which has politely requested a new coil and recoil starter after 19 years of faultless service. At least I can see (well, with glasses) what's wrong and put it right!

Mike

[#9]

The Cloudflare way of breaking bits of the internet, no matter what ISP.

(part 1)

https://www.theverge.com/2022/6/21/23176519/cloudflare-outage-june-2022-discord-shopify-fitbit-pelet...

Using cloudflare as a DNS resolving service is not a fix-all.

IMO.