[Pdns-users] PowerDNS vs UltraDNS??

Mark Bergsma mark at nedworks.org
Sat Feb 14 20:02:23 UTC 2004

Andrew Mulholland wrote:

>> The only thing there I see that may be interesting is this "Directional
>> DNS" stuff they talk about. Now a quick google shows that this is their
>> talk for some type of "use the nearest web server" result returned from
>> DNS. Now obvisouly I am gonna have to go away and have a look into this
>> as I have never heard of this being done using dns before. Does anyone
>> know if it can be done and if so, can PDNS (That magical brilliant piece
>> of art) do the same thing?
> it theoretically should be possible, if you write your own backend to 
> handle such stuff..
> To do it properly, would mean giving the DNS servers a BGP feed, and 
> writing some kind of algorithm to return result based on the lowest cost 
> path.
> This is how I believe the akadns.net stuff works, and also what BBC are 
> doing with news.bbc.co.uk.
> what might be easier, is doing it using one of the geoip type 
> things...(http://www.maxmind.com/) but might not always return people to 
> the closest mirror etc.

Coincidently, we have done exactly that, during the last week. We have 
written a new backend called 'geobackend', and is currently available 
via CVS only:




but it will appear in the main PowerDNS distribution soon.

It doesn't use geoip, but parses an rbldnsd zonefile containing the 
required information, such as the one from http://countries.nerd.dk.
(See the README file in CVS). We've been using it for a week now, and it 
has been very stable.

We are still thinking about ideas to improve it (on the geo-dns 
mailinglist, http://lists.blitzed.org/listinfo/geo ), so please let us 
about what you think. Returning IPs based on BGP info would be a nice 
feature, but we currently do not have a BGP session available.


mark at nedworks.org

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