effects of real low TTL ????

Re: effects of real low TTL ????

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Joe,

Keep in mind that the load balance record has a TTL of its own. Use
that, not the default TTL for the zone. We normally recommend a TTL
of 5 minutes (300 seconds) for load balance records.
____________________________________________________________________
Chris Buxton Men & Mice
support@menandmice.com Making DNS Easy

At 8:55 PM -0500 11/7/01, Joseph D'Andrea wrote:
>We've got an interesting scenario. A client in the UK has a web site
>that is tied to the UK release of the movie Shrek. We have the site
>loaded on two web servers and are load balancing between them. So
>far all is well.
>
>However, in a day or so, one of the largest ISPs in the UK with have
>a pop-up ad or some other mass advertisement for the site. We expect
>a significant number of people to visit just from this one provider
>alone. Since all of the people who use this provider presumably have
>the same DNS servers listed in their network setup, load balancing
>will not be very effective. In other words, the first person to
>visit the site will force the ISP to grab the IP address of the
>site, and every client after that from that same ISP will go to the
>same IP address because the IP address is cached in the ISP's DNS
>server.
>
>Now there will be lots of other people visiting the site from other
>ISPs, so there will be /some/ load balancing going on.
>
>What I'm thinking is that if I set the TTL of the domain real low...
>say one hour; and if the ISP respects the TTL and flushes its cache
>after that hour; then the next visitor from that ISP will force a
>new query and we'll have a 50/50 chance of it being the other server
>this time around. And so on and so on until the traffic dies down.
>
>Clearly there is some disadvantage to expiring an otherwise valid
>zone information just to force re-lookups... but are there other
>consequences that I'm not seeing?
>
>Thanks,
>___Joe___
>_________________________________________________
>Joseph D'Andrea JoeDan@West21.com
>WEST21.com Internet services for the 21st Century
> http://www.west21.com/
>_________________________________________________

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