Techniques for authenticating clients of differing capabilities in an efficient manner. Two or more authentication techniques, including one preferred authentication technique, are initiated to run in parallel to authenticate a client. Upon determining that the client can support the preferred authentication technique, the preferred technique is used to authenticate the client and the other authentication techniques are aborted. If it is determined that the client cannot support the preferred authentication technique, then one of the other authentication techniques is used to authenticate the client. In this manner, based upon the capabilities of the client, an appropriate authentication technique is used to authenticate the client in an efficient manner.