Anycast DNS - anybody?

2008-01-18 Thread Ewald Jenisch
Hi,

Has anybody out there configured anycast DNS (where multiple instances
of a DNS-server run under the same IP-address in different parts of
the network) under FreeBSD?

I'm looking for some hints to get started, but googling around didn't
provide much info on that topic...

Thanks much in advance for any clue.

Regards,
-ewald

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Re: Anycast DNS - anybody?

2008-01-18 Thread Javier Henderson
On Fri, 18 Jan 2008 16:02:14 +0100, Ewald Jenisch wrote:

 Has anybody out there configured anycast DNS (where multiple instances
 of a DNS-server run under the same IP-address in different parts of
 the network) under FreeBSD?

Yes.

Nothing really special on the FreeBSD side though. Just an alias 
address on one of the NIC's.

-jav
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Re: Anycast DNS - anybody?

2008-01-18 Thread Ashish Shukla आशीष शुक्ल
 Regarding Anycast DNS - anybody?; Ewald Jenisch [EMAIL PROTECTED] adds:
Ewald Hi,

Ewald Has anybody out there configured anycast DNS (where multiple 
instances
Ewald of a DNS-server run under the same IP-address in different parts of
Ewald the network) under FreeBSD?

AFAIK, anycast requires magic at routing level. So that user will
connect to the nearest DNS server (holding the anycast address).

Ewald I'm looking for some hints to get started, but googling around didn't
Ewald provide much info on that topic...

It has do with routing so you need to investigate on routing
protocols, like RIP, etc.

192.168.1.1 10.0.0.1network 10.0.0.2 192.168.1.1
 [server1] --- [router1]  =[router2] ---  [server2]

router1, router2 -- redundant routers connecting to different ISPs

So if router2 receives packet destined for 192.168.1.1, instead of sending to
server1 it'll send it to server2, since server2 is nearest to it, and
vice versa. Above is a very simple configuration describing anycast.

Since Anycast works only for connection-less protocols, you don't need
to keep TCP connections synchronized between two servers, although both servers
should behave identically, i.e. return similar records.

BtW, I've never implemented anycast ever, so its fully based on my imagination.

HTH
-- 
Ashish Shukla आशीष शुक्ल  http://wahjava.wordpress.com/
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