The present disclosure generally pertains to systems and methods for protecting network resources from denial of service attacks. In one exemplary embodiment, a responder stores an access filter value used to determine whether an incoming message frame has been transmitted from an authorized user. In this regard, a user communication device includes logic for determining the access filter value stored at the responder and, includes the access filter value in a message frame transmitted from the computer to the responder. The responder compares the received access filter value to the stored access filter value. If such values match or otherwise correspond, the responder authenticates the message frame. However, if such values do not match or otherwise correspond, the responder discards the message frame. Thus, the responder processes authenticated message frames and discards unauthenticated message frames thereby preventing denial of service attacks from malicious users.