Manpages - CURLOPT_FTP_SSL_CCC.3

CURLOPT_FTP_SSL_CCC - switch off SSL again with FTP after auth

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FTP_SSL_CCC, long how);

If enabled, this option makes libcurl use CCC (Clear Command Channel). It shuts down the SSL/TLS layer after authenticating. The rest of the control channel communication will be unencrypted. This allows NAT routers to follow the FTP transaction. Pass a long using one of the values below

CURLFTPSSL_CCC_NONE

do not attempt to use CCC.

CURLFTPSSL_CCC_PASSIVE

Do not initiate the shutdown, but wait for the server to do it. Do not send a reply.

CURLFTPSSL_CCC_ACTIVE

Initiate the shutdown and wait for a reply.

CURLFTPSSL_CCC_NONE

FTP

  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "ftp://example.com/file.txt");
    curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_CONTROL);
    /* go back to clear-text FTP after authenticating */
    curl_easy_setopt(curl, CURLOPT_FTP_SSL_CCC, CURLFTPSSL_CCC_ACTIVE);
    ret = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }

Added in 7.16.1

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

*CURLOPT_USE_SSL*(3), *CURLOPT_FTPSSLAUTH*(3),