Insufficeint privileges for SYS user

Time and again and again we see so many questions about INSUFFICIENT PRIVILEGES for the SYS when trying to login. I throw some tips that i have learned so far

1.Never use Oracle 8 Binary to connect as SYSDBA you will encounter INSUFFICIENT PRIVILEGES issue
I try to seggregate things here
2.a Connecting Localy in the server
2.b Connecting from remote

2.a Connecting Localy in the server :
Windows Connecting locally within the server When you set the value SQLNET_AUTHENTICATION_SERVICES=(NONE) in the sqlnet.ora you have to use passwordfile for authenticating .If passwordfile not available you have create and use it.you cant connect without a password file as simple as that. Even the REMOTE_LOGIN_PASSWORDFILE =NONE is set it does not allow without password

When you set the value SQLNET_AUTHENTICATION_SERVICES=(NTS)It doesnt care whether it has a passwordfile or not.But it check whether the system user is a member of a ORA_DBA group if not it will bounce with insufficient privileges .you should be a memeber of DBA to access the DB without password.

Connecting From Remote:

If you want to connect to the DB from a remote machine you should set REMOTE_LOGIN_PASSWORDFILE=EXCLUSIVE whereby which uses passwordfile to authntication to connect o the DB.Setting NONE will prevent user from connecting from the remote machine

BUt one strange i encnountered last week that i was not able to connect to DB as sys from remote machine with all variable set

Solaris 9 with Oracle 9.2.0.7.The issue was fixd with remote_os_authen=TRUE parameter.

I think it may be a bug

I will try in windows ..

Note:
1.Always set ORACLE_SID before trying to connect to the DB which fixes most of the issues
2.Unix-Check the ORacle user as a member fo DBA or OINSTALL group.
Most of the time we will be connecting to the wrong DB and gets bounced because of ORACLE_SID
S
Comments are welcome i might have