Ubuntu Manpage: CURLOPT_FTPPORT - make FTP transfer active

Provided by: libcurl4-doc_8.5.0-2ubuntu10.6_all

NAME

       CURLOPT_FTPPORT - make FTP transfer active

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FTPPORT, char *spec);

DESCRIPTION

Pass a pointer to a null-terminated string as parameter. It specifies that the FTP transfer should be
made actively and the given string is used to get the IP address to use for the FTP PORT instruction.

The PORT instruction tells the remote server to do a TCP connect to our specified IP address. The string
may be a plain IP address, a host name, a network interface name (under Unix) or just a '-' symbol to let
the library use your system's default IP address. Default FTP operations are passive, and does not use
the PORT command.

The address can be followed by a ':' to specify a port, optionally followed by a '-' to specify a port
range. If the port specified is 0, the operating system picks a free port. If a range is provided and all
ports in the range are not available, libcurl reports CURLE_FTP_PORT_FAILED for the handle. Invalid
port/range settings are ignored. IPv6 addresses followed by a port or port range have to be in brackets.
IPv6 addresses without port/range specifier can be in brackets.

Examples with specified ports:

eth0:0
192.168.1.2:32000-33000
curl.se:32123
[::1]:1234-4567

We strongly advise against specifying the address with a name, as it causes libcurl to do a blocking name
resolve call to retrieve the IP address. That name resolve operation does not use DNS-over-HTTPS even if
CURLOPT_DOH_URL(3) is set.

Using anything else than "-" for this option should typically only be done if you have special knowledge
and confirmation that it works.

You disable PORT again and go back to using the passive version by setting this option to NULL.

The application does not have to keep the string around after setting this option.

DEFAULT

       NULL

PROTOCOLS

FTP

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");
           curl_easy_setopt(curl, CURLOPT_FTPPORT, "-");
           res = curl_easy_perform(curl);
           curl_easy_cleanup(curl);
         }
       }

AVAILABILITY

       Port range support was added in 7.19.5

RETURN VALUE

       Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or CURLE_OUT_OF_MEMORY if there
       was insufficient heap space.