Route53 also has deeper integrations into Amazon therefore you can 'tag' services in that might change IP (via Elastic IP for example). You could do that with C

Route53 also has deeper integrations into Amazon therefore you can 'tag' services in that might change IP (via Elastic IP for example). You could do that with CNAME or ALIAS between the DNS providers but it'd get messy. Otherwise if you rotate an IP then you'll have to manually update the other DNS or write your own glue, or hand over delegation for certain namespaces in the domain in a frankenstein fashion. See also: Keeping sanity whilst maintaining hundreds of moving parts