My question is with regards to legacy dns entry while migrating from exchange 2007 to exchange 2013.
My understanding is as below, please correct me if I am wrong
Public IP: 42.22.36.158
Internal IP: 192.168.10.30
1. Create a Public DNS Entry for legacy.domain.com pointing to 42.22.36.158
2. Create a Internal DNS Entry for legacy.domain.com pointing to 192.168.10.30
3. Create a firewall rule routing nating all exchange services from legacy.platcorp.com (42.22.36.158) to Exchange 2007 server (192.168.10.30)
4. Reconfigure the external URL of the Exchange 2007 server
5. Add legacy.domain.com in the UC SSL certificate