DNS Help needed
 

ok tech question here TIA for help

Im moving to a new hosting company and am migrating my sites to the new server

when I am done how can I keep both sites up heres my idea but I dont know if it works...the goal is to keep both sites live until propagation happens fully

can I change the DNS info at the registrar so that I use

ns1.oldhosting.com
ns2.newhosting.com

and let that propagate for say 3 days then change it to

ns1.newhosting.com
ns2.newhosting.com

or am I going about this the wrong way and if so how do I avoid a site being unreachable during propagation?

Just set up the sites at your "new home" . Hopefully you get an IP. Then just change your dns. No down time

yes I have an IP at the new home...its a dedicated server I actually have IPs but im kind of...ok im totally ignorant about dns stuff the new home set up my own nameservers for me.

what exactly should I do to avoid the wait that I had last time when I changed the dns servers for say mikesouth.com and it took a few days to fully propagate so some people thought I was down for three days....am I explaining this right?

I want NO downtime even if it means the 2 sites may get out of sync

Setup your new DNS SERVER with the old ip address as A RECORD. switch nameservers Setup the new IP Numbers in your new dns.

Switched without downtime.

you da man thank you thank you thank you

if both servers are up during all the move there should be no downtime.
Also, the whole concept of propagation is kind of past now, with higher speeds and high processing power nowadays it's not every isp that has DNS caching servers, making everything faster.
So once you have made the change, it should come up almost instantly, as soon as you update the values, you just need to be sure that you don't have the site cached on your own machine.
To flush your DNS cache (using windows) you do open the command prompt and run:

some people like doing things the hard way I guess :Oh crap