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I need to setup my router to use opendns. It have the latest DDWRT firmware. But I want the router to act as a DNS server so it will cache the queries. I have set the Additional DNSMasq Options as follows :

no-resolv
strict-order
server=208.67.222.222
server=208.67.222.220

I have set the openDNS server for static dns servers and have added the following firewall rules to the router :

iptables -t nat -A PREROUTING -i br0 -p udp --dport 53 -j DNAT --to $(nvram get lan_ipaddr)
iptables -t nat -A PREROUTING -i br0 -p tcp --dport 53 -j DNAT --to $(nvram get lan_ipaddr)

According to this setup, Will the router forward all the dns requests to opendns without caching or will it cache?

  • Your router won't cache the dns requests but your computer will cache the dns information your router provides. – Ramhound Nov 28 '12 at 16:17
  • @Ramhound How to set the router to cache the requests? – THpubs Nov 28 '12 at 16:35
  • Your question wasn't clear so I provided an incorrect answered. How did you come up with that command if you don't know what it does? – Ramhound Nov 28 '12 at 17:45
  • @Ramhound Through the DDWRT wiki :) But there's no detailed explanation in there – THpubs Nov 29 '12 at 1:41
  • OpenDNS is a poor choice as it will insert ads where there should have been an NX reply. This can sometimes cause software to malfunction. And ads are something you should avoid. Pick a better DNS provider. And besides, spoofing DNS is hardly a proper security measure, no matter what you are trying to do. – Zdenek Dec 5 '16 at 16:43
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On the Services tab, under Additional DNSMasq Options, you can set these two options:

cache-size=0 
no-negcache 

From the DNSMasq man page:

Cache-size: Set the size of dnsmasq's cache. The default is 150 names. Setting the cache size to zero disables caching.

  • Hi, I need to enable caching and set it to first query opendns and then cache those requests – THpubs Nov 28 '12 at 17:02
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    @EApubs - So instead of setting the size of the cache to 0 pick some other number? – Ramhound Nov 28 '12 at 17:36
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    Yes. The number indicates the number of names that will be cached. – Ian Atkin Nov 28 '12 at 18:52

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