I found out by myself that changing the ip adress after the installation is a lot of trouble. do you have the possibility to setup a new server with the correct ip adress? this is way easier.
otherwise it would be helpful if you would tell us wich steps you were following.
greetings
@mlimburn have you read this thread? maybe it is helpful.
https://forums.fogproject.org/topic/6378/changing-ip-address-post-fog-install-is-problematic/27
there is provided a script that does a lot of ip changing, maybe using this script will get everything right and fix maybe forgotten entrys.