Provided herein are systems, devices and methods for applying address translation to network traffic originating from client devices having dynamic Internet Protocol (IP) addresses to support IP based security measures using a gateway configured to connect a plurality of client devices used by a plurality of users to a plurality of cloud based networks. The gateway may receive, from a client device assigned a dynamic IP address, credentials of a user using the respective client device, access a translation record mapping the user, identified by his credentials, to a respective unique static IP address, adjust a source address of each packet received from the client device to include the static IP address, and forward each adjusted packet to a security engine configured to apply security policy(s) to each adjusted packet before transmitting it to the cloud based network(s). The security policy(s) is applied according to the static IP address.