We recently moved to Exchange 2013 from 2007, and we're in Hybrid mode right now as we can't fully divorce from 2007 yet.
I was going over our DNS records and I found that for some reason our 2013 MB server has the same external dns record/IP as the old 2007 hub transport. I'm not sure if this is a mistake or done on purpose and I just forgot during the migration madness.
Our new 2013 CAS server has it's own external ip.
My question is, do both my 2013 CAS and 2013 MB server need IP's in external DNS? I'm still a little fuzzy on which server sends out the mail since the roles have changed (or do they both?). To be safe I was just going to give them both IP's so we don't get caught up in external spam problems.
Thanks,