1--- 2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3SPDX-License-Identifier: curl 4Title: CURLOPT_FTPPORT 5Section: 3 6Source: libcurl 7Protocol: 8 - FTP 9See-also: 10 - CURLOPT_FTP_USE_EPRT (3) 11 - CURLOPT_FTP_USE_EPSV (3) 12Added-in: 7.1 13--- 14 15# NAME 16 17CURLOPT_FTPPORT - make FTP transfer active 18 19# SYNOPSIS 20 21~~~c 22#include <curl/curl.h> 23 24CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FTPPORT, char *spec); 25~~~ 26 27# DESCRIPTION 28 29Pass a pointer to a null-terminated string as parameter. It specifies that the 30FTP transfer should be made actively and the given string is used to get the 31IP address to use for the FTP PORT instruction. 32 33The PORT instruction tells the remote server to do a TCP connect to our 34specified IP address. The string may be a plain IP address, a hostname, a 35network interface name (under Unix) or just a '-' symbol to let the library 36use your system's default IP address. Default FTP operations are passive, and 37does not use the PORT command. 38 39The address can be followed by a ':' to specify a port, optionally followed by 40a '-' to specify a port range. If the port specified is 0, the operating 41system picks a free port. If a range is provided and all ports in the range 42are not available, libcurl reports CURLE_FTP_PORT_FAILED for the 43handle. Invalid port/range settings are ignored. IPv6 addresses followed by a 44port or port range have to be in brackets. IPv6 addresses without port/range 45specifier can be in brackets. 46 47Examples with specified ports: 48 49 eth0:0 50 192.168.1.2:32000-33000 51 curl.se:32123 52 [::1]:1234-4567 53 54We strongly advise against specifying the address with a name, as it causes 55libcurl to do a blocking name resolve call to retrieve the IP address. That 56name resolve operation does **not** use DNS-over-HTTPS even if 57CURLOPT_DOH_URL(3) is set. 58 59Using anything else than "-" for this option should typically only be done if 60you have special knowledge and confirmation that it works. 61 62The application does not have to keep the string around after setting this 63option. 64 65Using this option multiple times makes the last set string override the 66previous ones. You disable PORT again and go back to using the passive version 67by setting this option to NULL. 68 69# DEFAULT 70 71NULL 72 73# %PROTOCOLS% 74 75# EXAMPLE 76 77~~~c 78int main(void) 79{ 80 CURL *curl = curl_easy_init(); 81 if(curl) { 82 CURLcode res; 83 curl_easy_setopt(curl, CURLOPT_URL, 84 "ftp://example.com/old-server/file.txt"); 85 curl_easy_setopt(curl, CURLOPT_FTPPORT, "-"); 86 res = curl_easy_perform(curl); 87 curl_easy_cleanup(curl); 88 } 89} 90~~~ 91 92# %AVAILABILITY% 93 94# RETURN VALUE 95 96Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or 97CURLE_OUT_OF_MEMORY if there was insufficient heap space. 98
