Increasing squirrelmail maximum attachment size

   1.  Locate your php.ini.
   2. open file is some editor.
   3. Search for upload_max_filesize.
   4. Change 2M to something else, for example 5M.
   5. If the upload_max_filesize is larger than post_max_size, you must increase post_max_size so that it’s bigger than upload_max_size
   6. If the value of post_max_size is larger than memory_limit, you must increase memory_limit so that it’s larger than post_max_size.
   7. Save your changes to the file.
   8. Restart your apache web server.

and enjoy using squirrelmail.