I'm moving my web application to another server and in the next few days I'll refresh the DNS to point to the new IP location.
Unfortunately some browsers and SOs keep a DNS cache that will make users point to the old IP location. Some users are rookies and they'll not refresh the DNS cache manually and I know we'll lose a lot of them in the first weeks after this change.
Is there anyway to force this DNS cache to refresh so it'll be transparent for our final users?
It might be possible to delete the Zone Record entirely, then recreate it exactly as you want it. Perhaps this will force a full propagation. If I'm wrong, somebody tell me and I'll delete this suggestion. Also, I don't know how to save a Zone Record and recreate it using WHM or any other tool.
I do know that when I deleted a hosting account today and recreated it, the original Zone Record seemed to be propagated instantly to a DNS resolver up the line from my computer. That is good evidence it works.
So if the issue is you just created a website and your clients or any given ISP DNS is cached and doesn't show new site yet. Yes all the other stuff applies ipconfig reset browser etc. BUT here's an Idea and something I do from time to time. You can set an alternate network ISP's DNS in the tcpip properties on the NIC properties. So if your ISP is say telstra and it hasn't propagated or updated you can specify an alternate service providers dns there. if that isp dns is updated before your native one hey presto you will see new site.But there is lots of other tricks you can do to determine propagation and get mail to work prior to the DNS updating. drop me a line if any one wants to chat.
There's no guaranteed way to force the user to clear the DNS cache, and it is often done by their ISP on top of their OS. It shouldn't take more than 24 hours for the updated DNS to propagate. Your best option is to make the transition seamless to the user by using something like mod_proxy with Apache to create a reverse proxy to your new server. That would cause all queries to the old server to still return the proper results and after a few days you would be free to remove the reverse proxy.
you can't force refresh but you can forward all old ip requests to new one. for a website:
replace [OLD_IP] with old server's ip
replace [NEW_IP] with new server's ip
run & win.
echo "1" > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A PREROUTING -d [OLD_IP] -p tcp --dport 80 -j DNAT --to-destination [NEW_IP]:80
iptables -t nat -A PREROUTING -d [OLD_IP] -p tcp --dport 443 -j DNAT --to-destination [NEW_IP]:443
iptables -t nat -A POSTROUTING -j MASQUERADE
If both of your servers are using WHM, I think we can reduce the time to nil. Create your domain in the new server and set everything ready. Go to the previous server and delete the account corresponding to that domain. Until now I have got no errors by doing this and felt the update instantaneous. FYI I used hostgator hosting (both dedicated servers). And I really dont know why it is so. It's supposed to be not like that until the TTL is over.
Source: Stackoverflow.com