404 not found , the requested URL <<url name>> not found on this server in wordpress

If it is a fresh install of web server it is possible that .htaccess rules are not allowed by default. To fix that, edit you httpd.conf (usually it is in /etc/apache2), find

<Directory "path/to/your/document/root">    
    # ....

     AllowOverride None

    # ....

</Directory>

and change

AllowOverride None

to

AllowOverride All

Then restart your web server and try again.