ORA-28009: connection to sys should be as sysdba or sysoper

I got a strange thing here, using SQL Plus as SysDBA is some what different than IMP.

To specify the connection string; you need the following format: username/password@instance as SYSDBA.

For SQL Plus:

This should be wrapped by double quotes "username/password@instance as SYSDBA"

For IMP:

This should be wrapped by single quotes 'username/password@instanceas SYSDBA' ; double quotes will not work.

Wired !