But I am confuse with a little part, i.e. referrer value? What referrer value?
Utkarsh Agrawal

When there is an error with requests to apache server like 404 errors, all the data of that error is written inside error.log file and you can set log format to take referer value of the request that caused error. So when I requested soap.php with curl referer switch ( -e https://stackoverflow.com/questions/23409952/what-does-curl-e-or-curl-referer-mean ) my referer value was written inside error.log file and executed.