We are doing a SBS 2011 to Exchange 2016 migration and we are using the migration guide (currently we are at step 8). At some point the firewall NAT rules have to be changed so ports 25 and 443 are routed to the new Exchange 2016 server instead of the old Exchange 2010. We believe this should be done at step 10 in the migration guide, is this correct?
Jelle,
It does not really matter when you do it as the 2016 server can down proxy to the 2010