NTLM compliant clients and servers are mutually authenticated in accordance with the Kerberos authentication protocol without migrating the clients or servers to Kerberos. With an RPC framework, a target name is generated from the server host name. The target name includes an indication that mutual authentication is to be accomplished. During the initial stages of the RPC session, the target name is sent to the server. If the server recognizes the target name, the client and server are mutually authenticated in accordance with the Kerberos protocol. If the server does not recognize the target name, the client is authenticated in accordance with the NTLM authentication protocol.