Magento 404 Page Notifier Extension is an extension which will send email notifications to admin if visitors try to open a page which is not available on your website for any reason (404 error page).
This extension also provides a separate managed grid in Magento backend with all the details regarding 404 pages. Admin can also export all 404 pages records in excel sheet.
Installation Steps
1 . Upload file manually – Extract it and then extract “Dev_Pagenotfound-1.0.0.tgz” and then copy all files app folder and then paste into your magento root directory.
2. Second way is from admin panel – Go to admin panel – System -> Configuration -> Magento Connect -> Magento Connect Manager and unchecked “Put store on the maintenance mode while installing/upgrading/backup creation” option and browse file and upload it.
3. Clear Cache
4. Now follow provide documentation or goto admin panel “System-> Configuration -> 404 Page Notifier -> General Settings” and check its options.