The blog discribes the customing of standard error pages from Web dispatcher and Custumizing error Page for Mantainmance Mode.
Blog Custom Error Messages in the Portal in the Portal explains how to customize the error messages at Application level. It allows you to have a different error page for different application or in general for all portal application deployed under /irj.While customizing error messages at Web Dispatcher will have a global error messages for different kind errors that can also be implemented for an ABAP system unsing Web Dispatcher.
h3. Customing of standard error pages from Web dispatcher
When error <ERRNAME> occurs, the ICM or Web dispatcher first checks whether file ICMERR‑<ERRNAME>.html sends it to the client. If it cannot find this file, it searches for ICMERR<ERRNAME>.shtml (Dynamic html page) and returns it. If no specific error page can be found, the ICM returns the default error page ICMERR-EDEFAULT.html. If this file also does not exist, the static page is returned.</p>h3. Custumizing error Page for Mantainmance Mode
5. Switching to Maintenance Mode