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
When encrypting SQL tables that have joins in SQL Server 2000, learn about possible problems that may arise with different data values in those ...continue reading
Learn how to set a SQL Server password to an SA login and why you can not set this account for access to separate SQL Server databases.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.