Edit httpd.conf for restricting the user to access it from specific IP address

I am using Ubuntu 14.04.2 LTS server.

I want to restrict user from accessing a sub-domain. So I searched across web, so this link I found helpful but I can not access /etc/apache2/httpd.conf file as it not exist.

So I searched for the better answer. I got this, But then I thought that I should make change in that domain conf file instead of following this link.

But Now I am thinking to make changes in conf file in /etc/apache2/sites-available folder for that domain.

Here is that file looks like

ServerAdmin info@domain.comServerName asd.domain.comServerAlias asd.domain.comDocumentRoot /var/www/public_html/asd.domain.com

And now I added one line as follows

Allow from <my.ip.address.000>

But now I am not able to restart the because Allow is not allowed.Can anybody help on this?