Oracle Error Message
ORA-12666: Dedicated server: outbound transport protocol different from inbound
Reason for the Error
The protocol specified for an externally-identified outbound connection from a dedicated server (database link) was not the same as that used for the inbound connection. It is not possible for Oracle Net to authenticate a proxy connection that uses a protocol that is different from that which was used for the connection to the dedicated server.
Solution
Specify the same protocol in the Oracle Net connect descriptor for the outbound connection as that used for the inbound connection.