1. A system comprising: a firewall installer to configure a firewall, the firewall installer comprising at least one processor programmed to: (A) receive, at the firewall installer, a set of configuration instructions comprising at least one configuration instruction, the set of configuration instructions being in a declarative form that specifies at least one firewall rule to be enforced by the firewall without specifying procedural steps to be carried out to configure the firewall to implement the at least one firewall rule; and (B) in response to receipt of the set of configuration instructions in the declarative form, modify a firewall policy of the firewall, via the firewall installer, such that the firewall implements the at least one firewall rule, wherein modifying the firewall policy comprises: (B1) determining whether the firewall is in operation, (B2) when it is determined that the firewall is in operation, communicating with the firewall to modify the firewall policy according to the set of configuration instructions, and (B3) when it is determined that the firewall is not in operation, making at least one edit to a data store comprising the firewall policy.