US Patent 9602538 Network security policy enforcement integrated with DNS server

A plug-in software module of a DNS server helps to enforce a network security policy. The plug-in module scans communication packets at a DNS server computer and intercepts a request from a user computer to access a web site. The intercepted request is not received by the DNS service. The plug-in module initiates a security check of the user computer over a network connection to determine if the user computer has implemented the security policy of the computer network. If the user computer does not implement the security policy then the plug-in module returns an IP address to the user computer that is the IP address of a security web site. The security web site then displays on the user's browser an indication of a security policy to be applied. The security web site may also perform the security check.