The invention provides a network security processing method and device. The method comprises the steps of judging whether a public network address of an external network sender exists in first verification information or not when an external network data request message sent by the external network sender is received; forwarding the external network data request message if the public network address exists in the first verification information and the state corresponding to the public network address of the external network sender in the first verification information is a first state; updating the first verification information according to a session state between the external network sender and an internal network sender if the public network address does not exist in the first verification information; and forwarding the external network data request message when the state corresponding to the public network address of the external network sender in the updated first verification information is the first state. Through application of the method and the device, the problem that in an existing NAT (Network Address Translation) scheme, an attacker can easily carry out a network attack on an internal network host through NAT table items is solved.