Hit your external DNS a few days before this move and make sure the TTL on those records is set real short.
From: Steve Hart [mailto:sh...@wrightbg.com] Sent: Friday, September 02, 2011 2:03 PM To: MS-Exchange Admin Issues Subject: Moving Exchange to Co-Lo Reconfigure all DNS (Internal and external) with the new addresses. --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to listmana...@lyris.sunbeltsoftware.com with the body: unsubscribe exchangelist