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I'm currently running a LAMP server with 2 IPs provided by 2 different ISPs. I use GoDaddy as my DNS manager but now that I have 2 IP addresses, I need the domain name to resolve the user to the fastest IP address for that specific user.

How do I go about doing this? I think I need an intelligent DNS that can figure out if the user is on the same ISP as the IP addresses.

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This sounds like a premature optimization for me. Simply use two DNS A-records instead. – Jonas Mar 22 '11 at 7:25
Actually, this is very common in China (Where I am located). You have two main ISPs (China Unicom and China Telecom), so many hosting providers allow your server to have 2 IPs. Users with Unicom will have significantly faster speeds on Unicom IP-addressed servers and Telecom users will be faster going to Telecom IP-addressed servers. – samxli Mar 22 '11 at 7:38
But if the user has the same ISP as your server, they should be routed to your server using that network by the ISP anyway. – Jonas Mar 22 '11 at 8:06
The hosting provider gave us a server with one ethernet card but it has the two IPs bound to it. – samxli Mar 22 '11 at 8:27
up vote 1 down vote accepted

I started using this service called They provide intelligent routing for the different ISP IPs in China via their DNS manager.

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If you want, try Ultradns.

Else personally, dont bother. Just create two A records to both IPS and then if you can, set a decent TTL for for the zone.


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Ideally you return both IPs and your user's system would use destination address selection to pick the right one. However, I believe that for IPv4 only some Windows versions do this.

When running your own name server is an option you can use bind with views to provide a different zone for different net ranges.

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