CURLOPT_FTP_SKIP_PASV_IP(3) Library Functions Manual CURLOPT_FTP_SKIP_PASV_IP(3)

CURLOPT_FTP_SKIP_PASV_IP - ignore the IP address in the PASV response

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FTP_SKIP_PASV_IP, long skip);

Pass a long. If skip is set to 1, it instructs libcurl to not use the IP address the server suggests in its 227-response to libcurl's PASV command when libcurl connects the data connection. Instead libcurl reuses the same IP address it already uses for the control connection. It still uses the port number from the 227-response.

This option allows libcurl to work around broken server installations or funny network setups that due to NATs, firewalls or incompetence report the wrong IP address. Setting this option also reduces the risk for various sorts of client abuse by malicious servers.

This option has no effect if PORT, EPRT or EPSV is used instead of PASV.

1 since 7.74.0, was 0 before then.

FTP

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "ftp://example.com/file.txt");
    /* please ignore the IP in the PASV response */
    curl_easy_setopt(curl, CURLOPT_FTP_SKIP_PASV_IP, 1L);
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

Added in 7.14.2

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

CURLOPT_FTPPORT(3), CURLOPT_FTP_USE_EPRT(3)

2024-05-22 libcurl