Set remote port number to work with
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PORT, long number);
This option sets number to be the remote port number to connect to, instead of the one specified in the URL or the default port for the used protocol.
Usually, you just let the URL decide which port to use but this allows the application to override that.
While this option accepts a 'long', a port number is usually a 16 bit number and therefore using a port number over 65535 will cause a run-time error.
By default this is 0 which makes it not used.
Used for all protocols that speak to a port number.