If you have some dollars to spend, I would look at Entercept (now owned by McAfee). Their host-based IPS is really top notch, and will prevent known and anomalous (unknown) attacks. Check out SQLSecurity.com for help locking down your database. The site's maintainer, Chip Andrews, is the person who coined the phrase "SQL injection" and has been an authority on securing databases for almost a decade.
IPsec between the Web and the database is a fantastic idea but realize this only protects against someone sniffing traffic between the two. If someone compromises the Web server, the IPsec tunneled between it and the database will still be intact. In fact, it will aid in cloaking the activities of the attacker from any network signature-based IDS that you may have in the DMZ (such as Snort).
Dig deeper on SQL Server Security
Related Q&A from Steven Andres
Find how to create a SQL Server 2000 login account and then set user account rights to specific databases with "db_owner."continue reading
Learn how to create a SQL Server user authentication schema having password and tracked data changes requirements and how it involves Windows ...continue reading
Learn why SQL Server 2000 connection is lost on the client side when database administrator changes 'SA' password on the SQL Server domain.continue reading
Have a question for an expert?
Please add a title for your question
Get answers from a TechTarget expert on whatever's puzzling you.