DNS problems with SafeDNS

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pmerrill
Posts: 290
Joined: Wed Feb 15, 2012 8:23 pm

DNS problems with SafeDNS

Post by pmerrill »

I am attempting to use SafeDNS as my DNS. This DNS has a schedule, so when it reaches a certain time some categories of sites are blocked and others are unblocked. It's a bit like OpenDNS but with a schedule.

In the last little while I have been having bad problems with this in that when the time is reached, the sites that were blocked don't turn back on. There are a few reasons this may happen, one of which is caching by either the PC or the router.

I found out that Gargoyle does DNS caching, so I turned this off by adding the following line to dnsmasq.conf.

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cache-size=0
I logged directly into gargoyle via putty (thus removing any interference with the windows dns cache) and did a nslookup of twitch.tv, which is a site that is blocked in the morning but should not be blocked in the afternoon. That command produced:

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# nslookup twitch.tv
Server: 127.0.0.1
Address 1: 127.0.0.1 locahost

Name: twitch.tv
Address 1: 195.46.39.1 blockpage.safedns.com
Clearly this is wrong as it's returning the blockpage. I even tried specifying the dns to use (as below) which I understand forces nslookup to use the dns at 195.46.39.39 (is that correct?).

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# nslookup twitch.tv 195.46.39.39
Server: 195.46.39.39
Address 1: 195.46.39.39 dns1.safedns.com

Name: twitch.tv
Address 1: 195.46.39.1 blockpage.safedns.com
But again it's returning the wrong page!!

The basic confirmation I'd like to get from the forum is. Is my logic correct? I don't believe caching is turned on at the router level, so I believe the problem exists at the SafeDNS end. Perhaps there is a way to check and see if the router cache is indeed turned off?

Many thanks for anyone who can provide help, this problem is driving me mad!

P.S. - If from my Windows PC I go into cmd screen, flush cache (ipconfig /flushdns) and do similar nslookups, I get the following:

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C:\Users\paula>nslookup twitch.tv
Server:  Gargoyle.lan
Address:  192.168.1.1

Non-authoritative answer:
Name:    twitch.tv
Address:  195.46.39.1

C:\Users\paula>nslookup twitch.tv 195.46.39.39
Server:  dns1.safedns.com
Address:  195.46.39.39

Non-authoritative answer:
Name:    twitch.tv
Address:  195.46.39.1
The thing that confuses me is that it indicates Non-authoritative answer which implies caching is happening somewhere, but where???
Paul
Gargoyle 1.11.x on TP-Link Archer C7 V2 H/W

ispyisail
Moderator
Posts: 5194
Joined: Mon Apr 06, 2009 3:15 am
Location: New Zealand

Re: DNS problems with SafeDNS

Post by ispyisail »

any update?

pmerrill
Posts: 290
Joined: Wed Feb 15, 2012 8:23 pm

Re: DNS problems with SafeDNS

Post by pmerrill »

It seems to be working now though I can't explain why. I think if you make a change, then you need to wait for the cache to clear. There must be some time limit on how long a reference is cached. Once it reaches that limit it starts working.
Paul
Gargoyle 1.11.x on TP-Link Archer C7 V2 H/W

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