curl / libcurl / API / curl_easy_setopt / CURLOPT_FTP_USE_EPSV

CURLOPT_FTP_USE_EPSV explained

Name

CURLOPT_FTP_USE_EPSV - use EPSV for FTP

Synopsis

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

Description

Pass epsv as a long. If the value is 1, it tells curl to use the EPSV command when doing passive FTP downloads (which it does by default). Using EPSV means that libcurl first attempts to use the EPSV command before using PASV. If you pass zero to this option, it does not use EPSV, only plain PASV.

The EPSV command is a slightly newer addition to the FTP protocol than PASV and is the preferred command to use since it enables IPv6 to be used. Old FTP servers might not support it, which is why libcurl has a fallback mechanism. Sometimes that fallback is not enough and then this option might come handy.

If the server is an IPv6 host, this option has no effect.

Default

Protocols

This functionality affects ftp only

Example

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL,
                     "ftp://example.com/old-server/file.txt");
 
    /* let's shut off this modern feature */
    curl_easy_setopt(curl, CURLOPT_FTP_USE_EPSV, 0L);
 
    res = curl_easy_perform(curl);
 
    curl_easy_cleanup(curl);
  }
}

Availability

Added in curl 7.9.2

Return value

Returns CURLE_OK if FTP is supported, and CURLE_UNKNOWN_OPTION if not.