CURLOPT\_LOCALPORTRANGE(3) Library Functions Manual CURLOPT\_LOCALPORTRANGE(3)

# [NAME](#NAME)

CURLOPT\_LOCALPORTRANGE - number of additional local ports to try

# [SYNOPSIS](#SYNOPSIS)

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_LOCALPORTRANGE,


                          long range);
```

# [DESCRIPTION](#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\_LOCALPORT(3)*](/man/os/curl/CURLOPT_LOCALPORT.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 numbers by nature are scarce resources that are busy at times so setting this value to something too low might cause unnecessary connection setup failures.

# [DEFAULT](#DEFAULT)

1

# [PROTOCOLS](#PROTOCOLS)

This functionality affects all supported protocols

# [EXAMPLE](#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](#AVAILABILITY)

Added in curl 7.15.2

# [RETURN VALUE](#RETURN_VALUE)

[*curl\_easy\_setopt(3)*](/man/os/curl/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)*](/man/os/curl/libcurl-errors.3).

# [SEE ALSO](#SEE_ALSO)

[**CURLOPT\_INTERFACE**(3)](/man/os/curl/CURLOPT_INTERFACE.3), [**CURLOPT\_LOCALPORT**(3)](/man/os/curl/CURLOPT_LOCALPORT.3)

2026-10-01 libcurl

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Document: CURLOPT_LOCALPORTRANGE(3) from curl 8.22.0-r4 (Chainguard OS)
Source: https://github.com/curl/curl.git