CURLOPT_FTP_SSL_CCC(3)

CURLOPT_FTP_SSL_CCC3

Switch off ssl again with ftp after auth

Usage

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

Overview

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 remains 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.

Default

CURLFTPSSL_CCC_NONE

Protocols

This functionality affects ftp only

Examples

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    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);
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

Return value

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).

Releases

7 releases since Debian 8 (Jessie); the text changed 6 times.

  1. 8
  2. 9
  3. 10
  4. 11
  5. 12
  6. 13
  7. Arch

History

CURLFTPSSL_* enums became long types in 8.16.0, prior to this version a long cast was necessary when passed to curl_easy_setopt(3).

Availability

Added in curl 7.16.1

From curl 8.23.0-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.