A request to authenticate is received (e.g., a request to login with a username/password). The request to authenticate comprises an address associated with the request to authenticate (e.g., an IP address). The request to authenticate is validated. In response to validating the request to authenticate, a message is sent to a routing device that identifies the address as authenticated for routing packets. In a second embodiment, a DHCP discover message is received. The DHCP discover message is a request to get an IP address. A determination is made to determine if the DHCP discover message comprises a watermark. In response to determining that the DHCP discover message comprises the watermark: a DHCP offer message is sent with an IP address and a third message is sent to a routing device that identifies the IP address as valid for routing packets.