원문 : http://www.ischo.net -- 조인상 //시스템 엔지니어

+++++++++++++++++++++++++++++++++++++++++++++++++++++++

28040, 0000, "No matching authentication protocol"
// *Cause:  There was no acceptable authentication protocol for
//          either client or server.
// *Action: The administrator should set the values of the
//          SQLNET.ALLOWED_LOGON_VERSION_SERVER and
//          SQLNET.ALLOWED_LOGON_VERSION_CLIENT parameters, on both the
//          client and on the server, to values that match the minimum
//          version software supported in the system.
//          This error is also raised when the client is authenticating to
//          a user account which was created without a verifier suitable for
//          the client software version. In this situation, that account's
//          password must be reset, in order for the required verifier to
//          be generated and allow authentication to proceed successfully.

원인 : 서버/클라이언트간 인증 프로토콜 차이

서버의 sqlnet.ora 파일에

SQLNET.ALLOWED_LOGON_VERSION = 9

라인 추가.