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Re: Slashdot: Providers Ignoring DNS TTL?
On Wed, 20 Apr 2005 email@example.com wrote: > > > I'd rather expect this sort of behavior with anycasted servers... > > Where do you see any connection between anycast and ignoring DNS TTL? > Or is this just part of your usual rant against anycast DNS service? The data he showed isn't necessarilly "ignoring ttl". If there are multiple anycasted caching servers behind a specific IP address, then those several cache's will each have a different state. Since, [as I explained, and was supposed by the poster], there is "some kind of load balancing going on", and also since implementors of anycast caches have posted questions and explained their purposes [which could be seen as "load balancing"], this is a likely explanation. It may not be the only explanation: e.g. they could be restarting their nameservers every thirty seconds. But "anycast loadbalancing" of a caching server is probably the most likely. But since you post on DNSOP, I assume that you read DNSOP [indeed, I may assume too much here], and so you have read the recent questions posed there on just how to implement just this sort of configuration. So, in light of that, I take your message to be your "usual [and fact-free] rant against anyone who explains the harms of anycast" > We use anycast for our caching (recursive) DNS servers. It works well > for us, and we certainly intend to continue to use it. The actual DNS > software used is Nominum CNS and BIND 9.3.1, both of which honor the > DNS TTL. "worked once for me" doesn't cut it, now. Does it? Probably you didn't notice that the cache states of different caching servers must be different. "load balancing" [of nearly any sort] and anycast does not work so well. > Steinar Haug, Nethelp consulting, firstname.lastname@example.org > > -- Av8 Internet Prepared to pay a premium for better service? www.av8.net faster, more reliable, better service 617 344 9000