On 17 June 2011 15:28, Shachar Shemesh <shac...@shemesh.biz> wrote: > On 06/17/2011 03:33 AM, Amos Shapira wrote: > >> I'm not sure what you are asking - DNS servers are supposed to be there in >> order to respond to queries, why shouldn't they answer queries? The slaves >> are there exactly as a back-up in case the master becomes unavailable. What >> else do you think they are there for? >> >> If at all - the usual setup is that the master is hidden behind a firewall >> and only the slaves answer queries. This is supposed to make it harder to >> inject bad records into the database since the secondaries should only read >> from a secure none-public server. >> >> BTW - if you have your own servers and your own IP address block then >> check options for using anycast to get DNS queries routed to the closest DNS >> server >> (http://en.wikipedia.org/wiki/**Anycast<http://en.wikipedia.org/wiki/Anycast> >> ). >> > The little I know of anycast, I'd be surprised if there were more than ~20 > organizations world wide that are capable of doing it. > You need to be managing your own IP address range (via BGP) as an entry > requirement. This means 1024 IP addresses, as that was BGP's minimal entry > level. You need to allocate that range exclusively for anycast use - you can > mix any cast and normal use over the same range. In other words, you can > only run anycast if you have dedicated server farms, each both quite big and > multiply connected, scattered around the world.
We have our own /22 block with our own AS number and BGP entries, operating from a tiny DC in California and a couple of colo srevers in London. I wouldn't say we are a very large operation (we are actually a tiny fish for now). Neustar have their entire business around this (anycast DNS with about 9 DC's around the world) and they don't seem to be a much bigger operation than ours. I doubt that's what Hetz has, though I can imagine that's what Google (or > GoDaddy) is doing. > That's why I suspect that at least part of Hetz' motivation to go it alone is just to play with the techie stuff more than a business sense. To me it makes much more sense to off-load such stuff to specialized providers so he can concentrate on his core value-added services. Though I admit I don't know his specific situation. --Amos
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