DNS changes - timing & effects

[craven]

Beginning 2 weeks ago, my server was hit numerous times by a hacker. Since then, I have changed hosts and moved all sites to the new server. My sites were supposed to stay intact on the old server for another month as well,
hopefully allowing Google the chance to find new DNS. However, for reasons beyond my control, the sites have been removed from the old server. What are the possible effects on Google and my rankings since they will have the old DNS info cached for this update? Worried that I will disappear from the serps...

Also, I'm already disappointed with the new hosting service and considering yet another move for my sites. Would this be a disaster at this point?

[NickCoons]

craven,

Your site could be completely offline and it shouldn't affect the update. You need to make sure that your site is accessible by Google during the deepcrawl.. that's when it's going to be important that they have new DNS information. If your site was crawled during the most recent one, then you shouldn't have a problem with the new index.

It's next month's update you should be worried about, if anything. I've heard from others that Google goes well over a month before updating their DNS cache, and then I've heard more recently that they are updating more frequently. By the time they crawl again, it'll probably be 3-4 weeks since your site was moved to the new host, and they may very well have updated their DNS cache.

[craven]

thank you for the help, i greatly appreciate it!

[dwilson]

Unfortunately, Google is not the only place where you may be hurt by the DNS caching. We would like to think that when your registrar makes the change in your DNS entry everyone will start getting the new IP address & finding you again. But other lower-level DNS servers cache the entry for performance' sake.

Your hosting company (or whoever actually controls your DNS) tells how long that caching is SUPPOSED to last. A cache of 1 day is typical, and not that huge a problem.

The problem gets truly problematic when some ISP's (notable AOL) set their DNS servers to actually cache the record for a month.

The best I can say is good luck. When I worked at a hosting company we learned this the hard way when our upstream provider made us change IP addresses. Hope you're with a solid, reliable, well-connected hosting company now.

dwilson