On Thursday 05 January 2006 13:15, John Hinton wrote:
It is important to use TTLs for the various services within a specified range. Too short will get you ignored, at least after a while. Too long.. same thing. I've never had a problem with setting the TTLs low for a few days before a transfer or some such, but then set them back up into acceptable ranges after the move.
Good help on the proper ranges can be found on http://dnsreport.com
Tried that. Suggestions? http://dnsreport.com/tools/dnsreport.ch?domain=schoolpathways.com
Five minutes will more than likely get you ignored after a few days or weeks. Imagine if everyone set their TTL to five minutes.. the root nameservers would be looking up every record on the net once every five minutes... a pretty arduous task for 13 servers. And if you want to find out what happens if you don't use cached DNS, try turning it off at the router level sometime for fun.... s--------l----------o----------w!!!! Heck, 1200bps dialups act like T-1s compared to no caching.
That's fine - but how do I minimize downtime in a failover scenario? (Thus, my questions about BGP, which you don't seem to mention)
In the past, when I 'cut down' the TTL to 5 minutes, I did so about 1 week before the switch. (that was the TTL on the domains, so it was the shortest I could do it.) I still had the aforementioned problem.
-Ben