Release 11i

1. Backup file $IAS_ORACLE_HOME/Apache/Apache/conf/apps.conf

2. Edit the apps.conf file and add a list of ip addresses for the users that you want to allow access to the system

Release R12.X, R12.1X

1. Edit file $ORA_CONFIG_HOME/10.1.3/Apache/Apache/conf/custom.conf and add a list of ip addresses for the users that you want to allow access to the system. The benefit of using custom.conf is that it is preserved when autoconfig is run.

Note, you need to include localhost and your apps tier server name. One can use the PC name rather than IP address, however PC name is more sensitive to network config

3. Restart Apache

4. Now only the users who are assigned to the ip addresses added will have access. All other users will get a forbidden error when they attempt to login.

This is a very simple solution and what makes it good is that it can be done programatically.

The forbidden error looks like this:

Forbidden
You don't have permission to access /OA_HTML/AppsLocalLogin.jsp on this server

If you want to change the message you can do this:

edit custom.conf

Add a line as follows (change the text to suit your requirements)
ErrorDocument 403 "Forbidden oops, you cannot access the production instance as it is month end, only certain users have access at this time.

Stop/Start apache. Users will now receive the above message.