CURLOPT_LOCALPORTRANGE(3)   Library Functions Manual   CURLOPT_LOCALPORTRANGE(3)

NAME
     CURLOPT_LOCALPORTRANGE - number of additional local ports to try

SYNOPSIS
     #include <curl/curl.h>

     CURLcode curl_easy_setopt(CURL *handle, CURLOPT_LOCALPORTRANGE,
			       long range);

DESCRIPTION
     Pass  a long. The range argument is the number of attempts libcurl makes to
     find a working local port number. It starts with the  given  CURLOPT_LOCAL-
     PORT(3) and adds one to the number for each retry. Setting this option to 1
     or below makes libcurl only do one try for the exact port number. Port num-
     bers  by nature are scarce resources that are busy at times so setting this
     value to something too low might cause unnecessary connection  setup  fail-
     ures.

DEFAULT
     1

PROTOCOLS
     This functionality affects all supported protocols

EXAMPLE
     int main(void)
     {
       CURL *curl = curl_easy_init();
       if(curl) {
	 CURLcode result;
	 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);
	 result = curl_easy_perform(curl);
	 curl_easy_cleanup(curl);
       }
     }

AVAILABILITY
     Added in curl 7.15.2

RETURN VALUE
     curl_easy_setopt(3) returns a CURLcode indicating success or error.

     CURLE_OK (0) means everything was OK, non-zero means an error occurred, see
     libcurl-errors(3).

SEE ALSO
     CURLOPT_INTERFACE(3), CURLOPT_LOCALPORT(3)

libcurl				   2026-09-14	       CURLOPT_LOCALPORTRANGE(3)