1. A method for providing a firewall rule for an application, the method comprising: receiving firewall rules from a plurality of clients, wherein each firewall rule regulates access by the application to one or more network communication functionalities; determining measures of trustworthiness for the plurality of clients from which the firewall rules are received, wherein determining a measure of trustworthiness for a client comprises determining a hygiene score indicating the client's propensity for getting infected by malicious code; determining at least one default firewall rule for the application based on the received firewall rules and the measures of trustworthiness for the plurality of clients from which the firewall rules are received; and providing the default firewall rule to a security agent executing on a second client, the security agent configured to configure a firewall using the provided default firewall rule.