Internal DNS Vs OpenDNS

Discussion in 'Tomato Firmware' started by Thomas Begley, Mar 11, 2015.

  1. Thomas Begley

    Thomas Begley Serious Server Member

    Hi guys,

    Can someone please give me some advice as to why my general internet page loading is much quicker using open dns servers than when i use the internal dns option.

    I am using shibby v1.24 on my Asus AC66U.

    Any help would be appreciated, if you need any more info please ask.

    Thanks in advance.
     
  2. rs232

    rs232 Network Guru Member

    It shouldn't be that way! I suggest:

    1) What DHCP servers is tomato using? are they opendns too?

    2) play with the DHCP / DNS Server parameters and see if things improve

    3) on the same page (Advanced/DHCP/DNS/Custom config) try to tweak the DNS cache with something like:
    cache-size=8096


    HTH
    rs232
     
  3. Monk E. Boy

    Monk E. Boy Network Guru Member

    Yeah, I would increase Tomato's cache size and make sure Tomato is using OpenDNS for resolution. It should be faster than going straight to OpenDNS, since it's fewer hops and that particular router should have more than enough CPU available for something trivial like a DNS server.

    With 256MB of RAM in the AC66 I'd just jump straight to the max, cache-size=10000. Even at max you're talking about using a couple MB of RAM for both IPv4 and IPv6 results.

    Try sticking this in your advanced DNS/DHCP section:
    #Only use DNS servers configured here
    no-resolv
    #Never forward non-routable address requests
    bogus-priv
    #Never forward requests w/o a .TLD
    domain-needed
    #No ACK and REQ spam
    quiet-dhcp
    #Larger cache for dnsmasq
    cache-size=10000
    #Larger queue for logging
    log-async=10
    #Block Windows proxy spam
    dhcp-option=252,"\n"

    #OpenDNS servers
    server=208.67.222.222
    server=208.67.220.220
    server=208.67.222.220
    server=208.67.220.222

    The # are just comments that explain what the following command does.
     
    mmosoll likes this.
  4. Thomas Begley

    Thomas Begley Serious Server Member

    Thank you both, i will give it a go. If using the no resolve option how do you define the ipv6 dns servers in the configuration. Thanks in advance
     
  5. Monk E. Boy

    Monk E. Boy Network Guru Member

    Hmm. Good question. You should be able to define them in the configuration file. If you're using OpenDNS for IPv4 resolution you probably would want to use OpenDNS for IPv6 resolution... According to OpenDNS the server IPs are 2620:0:ccc::2 and 2620:0:ccd::2 so that would translate to

    server=2620:0:ccc::2
    server=2620:0:ccd::2

    But I have NOT tested this. If you stick those lines in your config and dnsmasq fails to load, then comment them out and report back. According to the man page for dnsmasq that's the correct syntax. Check under status->logs for a line about dnsmasq failing to load, if you go there immediately after saving it should be in the last couple lines.

    Just for reference, the OpenDNS IPv6 page, and the DNSMasq man page.

    Keep in mind this only applies to IPv6 DNS lookups performed on the router itself. If your particular IPv6 setup doesn't rely on the router for DNS, if the router just proxies DHCP requests from your ISP, then the IPv6 lookups will still go out through whatever IPv6 DNS servers your ISP sends to your client. There are a billion ways to configure & assign IPv6 at this point, which is why I wrote this waffle paragraph...

    Oh, one last note, every time you save the config in advanced->dhcp/dns it reloads dnsmasq. When it reloads the cache is emptied. Until the cache fills, it will take slightly longer to resolve normal requests since the request goes you->router->DNS->router->you, once it has a goodly amount of entries cached many requests will go you->router->you.
     
    Last edited: Mar 13, 2015
  6. Thomas Begley

    Thomas Begley Serious Server Member

    Ok,tried the ipv6 and that seems to work. I think the issue with the slower dns reponce time was that i had adblocker enabled. Now that ive turned that off webpages seem to load much faster.
     
  7. Monk E. Boy

    Monk E. Boy Network Guru Member

    That's good to know (that server= lines work with IPv6 addresses). Thanks for reporting back.

    Did you have an adblocker on the router or in your browser? Because the former would make perfect sense for why it would take longer to resolve... the latter is a little confusing, since it should be apples to apples with no client side changes between the two, but maybe there's some extra overhead involved I'm not aware of.
     
  8. Thomas Begley

    Thomas Begley Serious Server Member

    I was using the lean clean adblock on the forums that was being run from my usb plugged into my router. I think when i disabled the use internal dns option is bypassed the adblocker hence causing the pages to load quicker.
     
  9. mmosoll

    mmosoll Networkin' Nut Member

    It's easy to confirm: Copy an host from your generated blocklist file by 'adblocks' in your browser to see if you can reach it. I will check it also tonight

    Note: May be I don't understand your question, I am also using adblocks but only with IPV4
     
    Last edited: Mar 16, 2015
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