True Usefulness of GeoDNS

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Posted by sandydpd, 08-09-2013, 11:56 AM
Generally, how accurate/useful is geoDNS? For example, if the user is using Google's DNS servers, wont that that always return the IP closest to the DNS server? If there are country-wide ISPs (like comcast?), wouldn't comcast's DNS also display whatever IP that is closest to their DNS server? Isn't that Is it generally more accurate throughout a country (for example, if I had 3 servers in the US, and wanted to route the user to the closest one), or more accurate country-wide? (i.e. 1 closest server for entire country)
Posted by InfiniteTech, 08-09-2013, 06:35 PM
It is as accurate as you describe, i.e. returns the IP closest to the DNS server. Consider using anycast as an alternative where the IP number itself remains constant, while its network location can be numerous.
Posted by sandydpd, 08-09-2013, 09:10 PM
I only have 3 servers, and am looking at keeping prices as low as possible - At the moment, I have 3 synchronized servers accross the US - one at Los Angeles, Dallas, and New York. The main issue I am finding is that Country-wide ISPs are caching the DNS queries, and sending that same DNS value to all the users on the network. I have thought of turning down the ttl to 10 or something, but it has resulted in millions (up to the 30 millions) of requests being generated
Posted by kaniini, 08-10-2013, 01:36 PM
Actually most public DNS resolvers like Google's or OpenDNS pass extended DNS (EDNS) subnet information, allowing for dynamic response generation.
Posted by sandydpd, 08-10-2013, 02:37 PM
That is the what I am facing right now - I dont know if its the geodns service I am using is having trouble, or if its just a geodns thing in general. For example: Using the domain "geo-region.sandydpnet.me" in the opendns cachecheck (http://www.opendns.com/support/cache/) completely returns the wrong results - the .15 address is located in NYC, theirs a .64 address that is located in Dallas, and a .81 address thats located in Los Angeles. Ive set the longitude/latitude manually in the geodns settings. Ive tried a few other services (http://www.whatsmydns.net/#A/geo-region.sandydpnet.me), (http://just-ping.com), and they are all giving me incorrect results. Ive seen edgedirector (My current provider is rage4), but I dont know if I would get better results than the current ones with it. Generally, I want Los Angeles to be serving Asia, South America, US West Coast, Canada West Coast, and Oceania, NYC to be serving East Coast, Canada East Coast, Europe, and Africa. Central US is to be served by Dallas. Last edited by sandydpd; 08-10-2013 at 02:41 PM.