DNS down - set your DNS servers manually

[#1]

History shows that we dont get notifications or follow-up from PN. I can remember a few PN issues over the last year including repeats -

- annual CPI increase not being applied to both the broadband and phone discounts so the final monthly amount appeared incorrect

- DNS failures September and yesterday

- updates to Chrome browser made the plus.net site inaccessible due to an outdated cert setup

The best status indication yesterday was downdetector - showing a spike even before posts here.

This compares with a recent power cut when we got immediate and follow-up texts - SMS is better than e-email notification if PN ever decide to keep customers better informed.

[#2]

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@Raxiel wrote:

According to Gibson's tool, Plusnet's own DNS is quite a bit faster than any of the others.

When it works.

[#3]

According to Gibson's tool, Plusnet's own DNS is quite a bit faster than any of the others.

If you are using a Plusnet connection, then Plusnet's DNS should be the fastest - access to any other will have to go via the Plusnet network so there's more latency for them.

However, unless you change the default servers tested the DNSBench tool, quite a few of them are US based - so are not necessarily the fastest available from the UK.

I run my own DNS server, and that is unsurprisingly an order of magnitude faster than the next best as the distance is much less.

[#4]

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@corringham wrote:

If you are using a Plusnet connection, then Plusnet's DNS should be the fastest

If you're NOT using a Plusnet connection, then the Plusnet DNS servers are unreachable !

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@corringham wrote:

According to Gibson's tool, Plusnet's own DNS is quite a bit faster than any of the others.

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That only seems to have happened since the new Plusnet DNS servers were put in (July 2023).

I used to frequently do DNS testing with the Gibson tool and Google's NameBench, and until the Plusnet DNS upgrade, the Plusnet DNS were a lot slower than the free alternatives and often showed about a 5% lookup failure rate (at any time of day),  but since the upgrade the Plusnet DNS speed is much better and I've not noticed any lookup failures.

[#5]

My Hub2

The reason I don't accept "Auto" on the Hub2 is that the DHCP server on the hub2 decides that the Hub2 is going to be the de-facto DNS server for everything that it assigns an IP to - if it is set to AUTO. Which (IMO) is a tad bit broken.

With non-AUTO and primary and secondary DNS manually set on the Hub2 all clients on the LAN receive DNS servers which have been manually set (i.e. .49 and .50, rather than 192.168.1.254)

My thoughts.The source code that underlies that possibly goes back to consumer grade home routers where the consumer could exercise local control on a subset of DNS (i.e. blocking certain domain names via the local 'router'). Previous versions of Plusnet supplied routers have acted in the same manner.

[#6]

What do you think you actually accomplish by changing the default settings? Your configuration uses the same IP subnet for both DNS servers giving a high probability that if one is inaccessible then so is the other.

Hub 2 passes all of GRC’s DNS vulnerability tests.

[#7]

@greygit1 wrote:

With non-AUTO ... ... ... all clients on the LAN receive DNS servers which have been manually set (i.e. .49 and .50, rather than 192.168.1.254)

@greygit1  -  Assuming what you are saying is true, why would you want to do that ?.

Every router that I've had for the last 20 years has had local DNS caching of all the previous DNS replies it has been asked to lookup by the network clients - therefore you should want to have the LAN client's DNS pointing at the router to get the speed benefit from accessing the local DNS cache.

If you're forcing router DHCP to handout external DNS server addresses to all of the LAN clients, then you are intentionally bypassing any router DNS cache, causing something like a 50x latency slowdown on each and every DNS request, and a huge increase in the number of external internet DNS requests+replies, unnecessarily using up your connection bandwidth.

[#8]

Well I didn't have problems Monday but constant disconnections Tuesday night/right now. Same thing? Stressful stuff.

[#9]

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@alexrpm wrote:
Well I didn't have problems Monday

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Either you were very lucky or you've set your router or devices to not use the PN DNS settings.

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but constant disconnections Tuesday night/right now.

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Maybe PN think you might have missed out and thought they'd give you the headache that some of us had on Monday

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Same thing?

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Probably not and if you have set up different DNS settings, were using a VPN or something like that then this recent DNS issue wouldn't affect your connection.

What's disconnecting?

• do you mean your router is disconnecting/rebooting?
• are wired and WiFi devices all dropping?

For info the router (or at least mine and all the other people I spoke with directly on Monday) remained lit in the normal way during the DNS issue.

Having said that (like I had to do fairly recently although before Mondays forum reported DNS issue) power cycling (as in turning it off and on at the mains) the router eventually fixed this recent issue, though it took 2 attempts about 90 minutes apart.

If you're on ADSL or FTTC and have a landline phone, dial 17070 and press the option for a quiet line test. Is the line quiet when 'she' isn't speaking?

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Stressful stuff.

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You're not wrong. I had to sit down in a darkened room from 6pm on Monday until around lunch time on Tuesday!!

If you can answer any of the above hopefully someone can jump in and assist you in the daylight hours later on.

[#10]

@alexrpm

Please start a new topic for your problem.

If you were not using your internet between approximately 4pm and 6pm on Monday, you would not have encountered the issue. There are also indications it did not impact everyone.

[#11]

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@corringham wrote:

According to Gibson's tool, Plusnet's own DNS is quite a bit faster than any of the others.

...

I run my own DNS server, and that is unsurprisingly an order of magnitude faster than the next best as the distance is much less.

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Isn't the router supposed to do that?

[#12]

Yes simple home router's do that, but only at the most basic level.

Running your own DNS server on your LAN allows you to do so many other things, such as -

• Blocking adverts being displayed on all of your home devices
• Geo-blocking lookups to countries that you might consider hostile
• Implementing your own parental blocking
• Allowing many more upstream DNS servers than the typical two that you often get
• Doing multiple simultaneous parallel DNS lookups, rather than the usual sequential primary then secondary then tertiary
• Have a massive DNS cache, rather than the typical limited 1000 entry cache
• Blocking lookups to BOGON and other suspicious internet addresses
• Returning IPv6 results to a home LAN (IPv6 enabled with a 6in4 tunnel) when the home router is IPv4 only.
• Having multiple home LAN subnets and VLANs, each with their own DNS rules (for guest, and children, etc)
• Allowing custom access from your home LAN to servers on your network that are internet facing
• Intercepting specific URLs and redirecting those to a different destination

I could go on and on,  but the benefits of having your own local DNS server are many !

[#13]

Most home routers provide a limited amount of DNS caching and that's all.

@Anonymous listed a number of features available if you run your own DNS server.

One I'd add is that I can provide a walled-garden for "guests" where (parts of) locally hosted web sites are only available within the LAN . I'll admit is isn't something most people would want to do, but it works for my use. 

[#14]

Clients have their own cache. Which may be the same as the router cache.

I have no way of checking what is cached on the router.

[#15]

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@Anonymous wrote:

@greygit1 wrote:

With non-AUTO ... ... ... all clients on the LAN receive DNS servers which have been manually set (i.e. .49 and .50, rather than 192.168.1.254)

@greygit1  -  Assuming what you are saying is true, why would you want to do that ?.

Every router that I've had for the last 20 years has had local DNS caching of all the previous DNS replies it has been asked to lookup by the network clients - therefore you should want to have the LAN client's DNS pointing at the router to get the speed benefit from accessing the local DNS cache.

If you're forcing router DHCP to handout external DNS server addresses to all of the LAN clients, then you are intentionally bypassing any router DNS cache, causing something like a 50x latency slowdown on each and every DNS request, and a huge increase in the number of external internet DNS requests+replies, unnecessarily using up your connection bandwidth.

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@Anonymous It would be great if you could get the router to set itself as the primary DNS and something else as the secondary.. that would be far too clever and failure-tolerant, though. 😉 

I totally get what you're saying about the router serving as a local DNS cache, I'm just now in a quandary about what to do... Do I want speed or stability? Seems I can't have both.  

Unless I wanted to run my own DNS server.. I'm not sure if I'm that invested emotionally. 😂