7800 - DNS Cache

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Carrot Cruncher
Posts: 28
Joined: Sun Nov 04, 2012 9:42 am

7800 - DNS Cache

Post by Carrot Cruncher » Thu Mar 12, 2015 12:24 pm

Hi. Does the 7800 cache DNS entries if you set "Use Router as DNS Server", and if so, how do you flush the cache? I've had a number of situations where I've changed the DNS server for a domain and yet performing lookup against the router does not reflect the change.

For example, I currently have the router configured as a DNS server using a Google DNS as the primary and then one of my ISP's DNS as the secondary, these are the results I get:

Google:
nslookup {domain} 8.8.8.8
Server: 8.8.8.8
Address: 8.8.8.8#53

Non-authoritative answer:
Name: {domain}
Address: 31.216.52.130

ISP:
nslookup {domain} 90.207.238.99
Server: 90.207.238.99
Address: 90.207.238.99#53

Non-authoritative answer:
Name: {domain}
Address: 31.216.52.130

Router:
nslookup {domain} 192.168.10.1
Server: 192.168.10.1
Address: 192.168.10.1#53

Non-authoritative answer:
Name: {domain}
Address: 31.216.52.129

31.216.52.130 is the new address and 31.216.52.129 is the old address. Cheers.

Carrot Cruncher
Posts: 28
Joined: Sun Nov 04, 2012 9:42 am

Re: 7800 - DNS Cache

Post by Carrot Cruncher » Thu Mar 12, 2015 12:29 pm

Sorry. I should have added that, if I disconnect the ADSL connection, the router still responds to recent DNS lookups so this would suggest it is using cached entries.

The only way I've found to get the correct responses is to reboot the router, so a simple flushing option would be great.

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