CURLOPT_LOCALPORT - local port number to use for socket
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_LOCALPORT, long port);
Pass a long. This sets the local port number of the socket used for the
connection. This can be used in combination with CURLOPT_INTERFACE(3)
and you are recommended to use CURLOPT_LOCALPORTRANGE(3) as well when
this option is set. Valid port numbers are 1 - 65535.
0, disabled - use whatever the system thinks is fine
CURL *curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");
curl_easy_setopt(curl, CURLOPT_LOCALPORT, 49152L);
/* and try 20 more ports following that */
curl_easy_setopt(curl, CURLOPT_LOCALPORTRANGE, 20L);
ret = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
CURLOPT_LOCALPORTRANGE(3), CURLOPT_INTERFACE(3),