A system of the invention comprises first and second computers. The first computer retrieves and incorporates its security state data in a message requesting a network connection with the second computer. The second computer receives the message and determines whether its security policy data permits connection with the first computer given the security state of the first computer as indicated by its security state data. The security state data can comprise data indicating whether an anti-virus application, firewall application, or operating system are running on the first computer, and are up-to-date. If so, the second computer permits the network connection to proceed. If not, then the second computer either drops the connection request or terminates the connection request by transmitting a disconnection message to the first computer. The invention also comprises related apparatuses, methods, and computer-readable media.