SPNEGO SPNEGO (Simple and Protected GSSAPI Negotiation Mechanism) is a GSSAPI "pseudo mechanism" that is used to negotiate one of a number of possible real mechanisms.SPNEGO is used when a client application wants to authenticate to a remote server, but neither end is sure what authentication protocols the other supports.The pseudo-mechanism uses a protocol to determine what common GSSAPI mechanisms are available, selects one and then dispatches all further security operations to it.