SQL firewalls are newcomers to the world of content security and firewalls. Historically, most SQL firewalls have been internal solutions built on various firewall and proxy frameworks such as Windows Sockets (SOCKS). However, vendors have now shifted to appliance-based firewalls (firewalls packaged as standalone, hardware-based black boxes) because customers prefer plug-and-run security products that insert easily into the network. Here is a sampling of companies that offer SQL firewall products, including the company I work for: