I'm testing simple API with cURL. It's, calling from (a php file of) one Apache Server to (a php file of) another Apache Server. It's ok testing in your area. However when i test with my network Computers, it showing following 403 error:

Access forbidden! You don't have permission to access the requested object. It is either read-protected or not readable by the server. If you think this is a server error, please contact the webmaster. Error 403

Codes for Caller Server (Server 1) are:

function apicall($request_url) {
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $request_url);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 10);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    $return = curl_exec($ch);
    curl_close($ch);
    return $return;
}
$request_url = 'http://192.168.1.205/api.php?cname=David';
$response = apicall($request_url);


Codes for Responding to Server (Server 2) are:

echo "Hello ".$_GET['cname'];

cURL is enabled on Apache. Why? What should i do?

This really is nothing related to cURL, it's your Apache configuration that's the issue.

Apache is set up in a way the the resource at api.php isn't open to the equipment which your script is running.

In your soul Apache configuration, for that root directory, you have to inspect these directives:

# Yours will not look like this
# The key point is look at the 'Order' and 'Allow'/'Deny' directives for the root directory
Order allow,deny
Allow from all

Take a look at this and also the sections immediately below it.

Alternatively, you might have some code somewhere in api.php that appears something similar to this:

header('HTTP/1.1 403 Forbidden');
exit("Access forbidden!\nYou don't have permission to access the requested object. It is either read-protected or not readable by the server.\nIf you think this is a server error, please contact the webmaster.\nError 403");

...however, according to that which you have to say is inside your code, I believe this is one of the Apache configuration.

If you work with WAMP, make certain you "put online" the server.

Next,

Is that you simply htaccess obstructing it ?