I just setup a CPanel server but I'm having a few problems because of ISPs using old DNS. I was using a different control panel software and each site was assigned a static IP address. I am now using only one IP address for all sites (name based hosting).
The problem is the sites are still resolving to their old IP addresses because I failed to set the TTL to a lower value.
My questions is, what do you think is the most amount of time it will take to have ISPs get an updated version of the info (I have never changed the BIND default) and is there any way to quicken the process?