I'm developing a B2B website open to the internet.
I've deployed the website on an application server that is in its own network and is only allowed to communicate to the intranet on two ports:
- To an Exchange Server and
- to a SQL Server,
both of which are in the internal network.
I want to limit the damage in the scenario in which the application server gets compromised.
I'm especially concerned with SQL Server, as exploits are known to exist on occasion.
There is the (involved) option to work with two databases, one on the application server and one being internal, and a syncing method between them. In that case, the only connection would be initiated from the local network to the application server rather than the other way round. That would exclude most exploits I believe.
I would like to hear what people find reasonable and what else there is to recommend.