CURLOPT_FTPSSLAUTH(3) Library Functions Manual CURLOPT_FTPSSLAUTH(3)

CURLOPT_FTPSSLAUTH - order in which to attempt TLS vs SSL

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

Pass a long using one of the values from below, to alter how libcurl issues "AUTH TLS" or "AUTH SSL" when FTP over SSL is activated. This is only interesting if CURLOPT_USE_SSL(3) is also set.

Possible order values:

Allow libcurl to decide.
Try "AUTH SSL" first, and only if that fails try "AUTH TLS".
Try "AUTH TLS" first, and only if that fails try "AUTH SSL".

CURLFTPAUTH_DEFAULT

FTP

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "ftp://example.com/file.txt");
    curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_TRY);
    /* funny server, ask for SSL before TLS */
    curl_easy_setopt(curl, CURLOPT_FTPSSLAUTH, (long)CURLFTPAUTH_SSL);
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

Added in 7.12.2

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

CURLOPT_FTP_SSL_CCC(3), CURLOPT_USE_SSL(3)

2024-05-22 libcurl