I have an AD2003 native environment with (2) servers at our seattle site. DC1 is the GC and all FSMO roles with AD integrated DNS. This is the one which Exchange coughs over when it's rebooted. The other server (DC2) is AD integrated DNS and DHCP server holding all the scopes for this site. I have to move both and then our Exchange Cluster (2 nodes in active/standby) to a new subnet. We will be routing between the 2 subnets until the migration is complete. The DC's are replicating with other pgysical sites across WAN links. My concerns involve the steps and sequencing for DNS reverse lookup zones, replication partners, standby partners (never designed in the first place currently) and of course, the potential for breakign Exchange. I wish I could offer more than 500 for this somehow. I've read some of the links and other solutions already. Please don't point me to MS KB's unless they truly apply to exactly my situation. Thanks all!!!