Sqlplus login without password

Question

I installed Oracle 11gR2 on my linux server. When I want to login via sys user on my db, I enter "sys as sysdba" and when system give password , I push enter and I can login on my db with sqlplus.

But, when I try to connect on Windows with PL-SQL tool, system wants to password. If I didn't write password (I defined password, password is "sys"), I cannot login on my db.

Why?

Solution 1

When you install oracle, it creates OSDBA and OSOPER groups. Any members of this groups will have OS authentication and can logon without a password.

When you connect from another machine, it's a remote connection and you must enter the password.

More info in the documentation.

Solution 2

When you connect on the same server you're being authenticated by the operating system; you can give any password you like, or it's more common to use / as sysdba.

When you connect from PL/SQL it'a a remote connection; operating system authentication isn't possible, so you're using password authentication.