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Re: [dnsop] DNS Anycast revisited (fwd)

  • From: Patrick W. Gilmore
  • Date: Wed May 04 00:37:52 2005 
On May 3, 2005, at 10:28 PM, Nicholas Suan wrote:


In the previous paragraph Vixie said:
while i'm on the subject, i also remain convinced that using anycast to do
distributed load balancing for applications like WWW, on the assumption
that the path you heard a dns query on is instructive as to what content
would be best to answer with, is silly, and will more often do harm or do
nothing than do good. (and i've told akamai and speedera this many times.)
("but it makes for great marketing slideware.")

In other words this is a bad idea:

[[email protected] FT]$ dig a248.e.akamai.net @69.45.79.10

;; ANSWER SECTION:
a248.e.akamai.net. 20 IN A 80.67.72.214
a248.e.akamai.net. 20 IN A 80.67.72.201

[email protected]:~$ dig a248.e.akamai.net @69.45.79.10

;; ANSWER SECTION:
a248.e.akamai.net. 20 IN A 69.45.79.15
a248.e.akamai.net. 20 IN A 69.45.79.16

While I'm not a mind reader, It seems he's saying that, since Ultradns doesn't use anycast to do this, it is an example of 'good anycast.'
I'm not a mind reader either, but I read English. (Well, I try sometimes. :) Paul said:

<quote>
i also remain convinced that using anycast to do distributed load balancing for applications like WWW, ... is silly, and will more often do harm or do nothing than do good. (and i've told akamai and speedera this many times.)
</quote>

The fact your digs returned different IPs for the same hostname has _nothing_ to do with anycast.

Whether (or not) UltraDNS doing this (or not) is good (or not) seems, to me at least, to be apples & oranges.

--
TTFN,
patrick