Role of APPLSYSPUB, GUEST, APPLSYS, APPS users:

Role of APPLSYSPUB user/schema in Oracle Applications:

When we login to applications,initially oracle applications connect to public schema, APPLSYSPUB. This schema has sufficient privileges to perform the authentication of an Applications User (FND user), which includes running PL/SQL packages to verify the username/password combination and the privilege to record the success or failure of a login attempt.

• The public ORACLE username and password that grants access to the Oracle E-Business Suite initial sign-on form. The default is APPLSYSPUB/PUB.

• Once we change the APPLSYSPUB password must propagate the change to application tier configuration files. If the instance is Autoconfig enabled, must edit the CONTEXT file on each tier prior to running Autoconfig.

• In the CONTEXT file, locate the autoconfig variable “s_gwyuid_pass” and set it to the new password, then run AutoConfig in each applications nodes.

When Autoconfig is not being used:

If you are not using Autoconfig you must manually edit the following configuration files :

1) FND_TOP/resource/appsweb.cfg
2) OA_HTML/bin/appsweb.cfg
3) FND_TOP/secure/HOSTNAME_DBNAME.dbc

To change password of APPLSYSPUB with FNDCPASS:
$FNDCPASS APPS/[apps_pass] 0 Y SYSTEM/[system_pass] ORACLE APPLSYSPUB [new_passs].

0 & Y are flags for FNDCPASS
0 is request id (request ID 0 is assigned to request ID's which are not submitted via Submit Concurrent Request Form)
'Y' indicates that this method is directly invoked from the command-line and not from the Submit Request Form.

• All application tier processes (Apaches) must be restarted following the password change.

Role of GUEST user/schema in Oracle Applications:

• GUEST is a dummy schema.

• By default it has ORACLE as password.

• GUEST/ORACLE password is present in DBC file at $FND_TOP/secure directory as well as at $FND_TOP/secure/SID_hostname directory.

• If a user logs in without any role mappings, the user will get the Guest role, which has a default permission of "R".

• GUEST user is used by JDBC Drivers and Oracle Self Service Web Applications like istore, irecruitment, iprocurement, ipayables, ireceivables etc to make initial Connection.

Role of APPLSYS & apps user/schema in Oracle Applications:

• APPLSYS user is same as other oracle users like AP, AR, GL etc which hold their set of tables, views etc. In the same manner APPLSYS Account holds its set of tables like FND_USER and FND_APPLICATION, AD_APPLIED_PATCHES etc.

• Applsys schema has applications technology layer products like FND and AD etc.

• Apps is a universal schema, it has synonyms to all base product tables and sequences. This also has code objects for all products (triggers, views, packages, synonyms etc).

• APPS is central Schema which holds synonyms for all other Users Database Objects.

Note: APPLSYS and APPS should have same password.

Reason why these contains same password.

Both apps & applsys need to have same password because when you sign on to apps, initially it connects to a public schema called APPLSYSPUB. This validates AOL name and password that we enter (operations/welcome). Once this is verified we select responsibility, this is validated by APPLSYS schema and then it connects to apps schema.
During signon process it uses both applsys and apps, hence this expects both the password to be identical. If the password for applsys & apps are not identical (Different) Try changing apps password to something else and try to login, the validation at the last stage would fail. This would result in failure of application login.

Difference B/W APPLSYSPUB & GUEST:

• APPLSYSPUB/PUB - is DB user which is used by any utility to retrieve APPS schema password for further logins.

• GUEST/ORACLE - is EBS user with no or max limited privileges to execute authorization function.

  Thanks 

  Srini