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MrZipf2
Aspiring Contributor
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Message 11 of 19

Re: Unreachable sites.

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That's a good spot. The DNS servers the HH5 using are serving the same address for goo.gl, feeds.feedburner.com, and quizlet.com. And they are all broekn.

 

TCP/IP settings
Broadband network IP address:86.171.XXX.YYY 
Default gateway:217.32.145.0 
Primary DNS:213.120.234.10 
Secondary DNS:213.120.234.58

 

Whilst I can change it, that'll break BT's parental controls (which is the only thing that keeps me with BT). As a parent, I can't sit with the kids every minute they're on the internet. I guess we can change it long enough for our youngest to be able to do his Spanish assignments on quizlet.com.

 

WRT to powering off and back again, the modem has a battery backup - disconnected it and the internet keeps chugging away. Unfortunately the front panel is not readily accessible otherwise I'd hit the reset switch. [ Behind enormous bookcase with solid back ].

 

So now we have BT serving bad DNS records for FTTP customers. All we need now is someone at BT to give a hoot.

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smf22
Recognised Expert
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Message 12 of 19

Re: Unreachable sites.

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Odd thing is though that those BT DNS servers give me the same answer as Google.

 

C:\Users\smf22>nslookup quizlet.com 213.120.234.10
Server:  indnsc90.ukcore.bt.net
Address:  213.120.234.10

Non-authoritative answer:
Name:    quizlet.com
Addresses:  104.16.18.221
          104.16.15.221
          104.16.17.221
          104.16.16.221
          104.16.14.221

C:\Users\smf22>nslookup quizlet.com 8.8.8.8
Server:  google-public-dns-a.google.com
Address:  8.8.8.8

Non-authoritative answer:
Name:    quizlet.com
Addresses:  104.16.18.221
          104.16.15.221
          104.16.16.221
          104.16.17.221
          104.16.14.221

If you're able to change the DNS server on the client you could try different BT DNS servers so as not to break the parental controls. Here's some that I know of:

 

62.6.40.162
62.6.40.178

194.72.0.98
194.72.0.114

194.74.65.68
194.74.65.69

 

Regards

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MrZipf2
Aspiring Contributor
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Message 13 of 19

Re: Unreachable sites.

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That's really interesting. If I flush DNS and use the same DNS server, the result is the broekn BT address:

 

> ipconfig /flushdns
Windows IP Configuration
Successfully flushed the DNS Resolver Cache.

> nslookup quizlet.com 213.120.234.10
Server: indnsc90.ukcore.bt.net
Address: 213.120.234.10
Non-authoritative answer:
Name: quizlet.com
Address: 81.139.58.97

I get the same result from the other BT DNS servers, eg

 

> nslookup quizlet.com 194.74.65.68
Server: indnsc41.ukcore.bt.net
Address: 194.74.65.68
Non-authoritative answer:
Name: quizlet.com
Address: 81.139.57.97

> nslookup quizlet.com 62.6.40.162
Server: indnsc71.ukcore.bt.net
Address: 62.6.40.162

Non-authoritative answer:
Name: quizlet.com
Address: 81.139.56.97

Spooky...

 

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MrZipf2
Aspiring Contributor
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Message 14 of 19

Re: Unreachable sites.

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There is a similar thread on plusnet with other addresses resolving to same BT address:

 

https://community.plus.net/t5/Fibre-Broadband/Cannot-connect-to-some-websites/td-p/1388384/highlight...

 

No real solution there bar switching to an external DNS server which is fine modulo breaking parental controls.

 

Anyone from BT want to comment on why your DNS has this issue? 

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MrZipf2
Aspiring Contributor
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Message 15 of 19

Re: Unreachable sites.

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Turning off parental controls "fixes" this issue, I tried it* and the broekn DNS behaviour goes away.

 

Parental controls turned on and the broekn resolutions are back.

 

BT, why does enabling parental controls result in bad DNS resolutions for common sites?

 

[ Only works from IE/Firefox, page goes into a loop with Chrome 54 ].

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MrZipf2
Aspiring Contributor
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Message 16 of 19

Parental controls produces bad DNS results for sites

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We have BT Parental Controls enabled on our HH5 and connectivity to the BT network over FTTP.

 

DNS responses to a number of popular services resolve to an unreachable address. It's always the same address: 81.139.58.97

 

Example services broken:

  • goo.gl
  • feeds.feedburner.com
  • quizlet.com

Turning off BT's Parental Control results in resolutions that are reachable on the public Internet. 

 

There's a thread here on how we figured this out:

 

https://community.bt.com/t5/BT-Infinity-Speed-Connection/Unreachable-sites/td-p/1694842

 

BT support , why are these resolutions broken? Thanks

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MrZipf2
Aspiring Contributor
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Message 17 of 19

Re: Unreachable sites.

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Opened a thread in the BT Extras forum as this seems more appropropriate.

 

https://community.bt.com/t5/Broadband-Extras-from-BT/Parental-controls-produces-bad-DNS-results-for-...

 

Thanks to jmf22 for help in getting this far.

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MrZipf2
Aspiring Contributor
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Message 18 of 19

Re: Parental controls produces bad DNS results for sites

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In case it's not obvious, visiting these services produces nothing. No parental warning page, just an opening TCP handshake that never completes. Your parental controls breaks podcast serving from feedburner, Google URL shortener, and the site where my son is supposed to practise his Spanish for school.

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MrZipf2
Aspiring Contributor
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Message 19 of 19

Re: Parental controls produces bad DNS results for sites

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FTR, manually adding the sites to the approved sites in parental controls enables them to resolve.

 

This cannot be WAI, black holing requests with no warning page?

 

 

 

 

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