CURLOPT_LOGIN_OPTIONS(3) Introduction to Library Functions
CURLOPT_LOGIN_OPTIONS - login options
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_LOGIN_OPTIONS, char *options);
Pass a char pointer as parameter, which should be pointing to the
null-terminated options string to use for the transfer.
For more information about the login options please see RFC 2384, RFC
5092 and the IETF draft draft-earhart-url-smtp-00.txt.
CURLOPT_LOGIN_OPTIONS(3) can be used to set protocol specific login
options, such as the preferred authentication mechanism via
"AUTH=NTLM" or "AUTH=*", and should be used in conjunction with the
CURLOPT_USERNAME(3) option.
Since 8.2.0, IMAP supports the login option "AUTH=+LOGIN". With this
option, curl uses the plain (not SASL) LOGIN IMAP command even if the
server advertises SASL authentication. Care should be taken in using
this option, as it sends your password in plain text. This does not
work if the IMAP server disables the plain LOGIN (e.g. to prevent
password snooping).
The application does not have to keep the string around after setting
this option.
Using this option multiple times makes the last set string override
the previous ones. Set it to NULL to disable its use again.
CURLOPT_LOGIN_OPTIONS(3) is a login property, it does not change the
security context. This means that this option changes how the login
happens when a connection is created, but it does not affect which
connections libcurl can reuse. libcurl may reuse a connection that
was set up with a different options string; a different options
string does not by itself prevent reuse. Connection reuse still
depends on other connection properties matching, such as the
protocol, hostname, port number, credentials and other settings that
affect the connection.
NULL
This functionality affects imap, ldap, pop3 and smtp
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode result;
curl_easy_setopt(curl, CURLOPT_URL, "smtp://example.com/");
curl_easy_setopt(curl, CURLOPT_LOGIN_OPTIONS, "AUTH=*");
result = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
Support for OpenLDAP added in 7.82.0.
Added in curl 7.34.0
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).
CURLOPT_PASSWORD(3), CURLOPT_USERNAME(3)
libcurl 2026-04-29 CURLOPT_LOGIN_OPTIONS(3)
NAME
CURLOPT_LOGIN_OPTIONS - login options
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_LOGIN_OPTIONS, char *options);
DESCRIPTION
Pass a char pointer as parameter, which should be pointing to the
null-terminated options string to use for the transfer.
For more information about the login options please see RFC 2384, RFC
5092 and the IETF draft draft-earhart-url-smtp-00.txt.
CURLOPT_LOGIN_OPTIONS(3) can be used to set protocol specific login
options, such as the preferred authentication mechanism via
"AUTH=NTLM" or "AUTH=*", and should be used in conjunction with the
CURLOPT_USERNAME(3) option.
Since 8.2.0, IMAP supports the login option "AUTH=+LOGIN". With this
option, curl uses the plain (not SASL) LOGIN IMAP command even if the
server advertises SASL authentication. Care should be taken in using
this option, as it sends your password in plain text. This does not
work if the IMAP server disables the plain LOGIN (e.g. to prevent
password snooping).
The application does not have to keep the string around after setting
this option.
Using this option multiple times makes the last set string override
the previous ones. Set it to NULL to disable its use again.
CURLOPT_LOGIN_OPTIONS(3) is a login property, it does not change the
security context. This means that this option changes how the login
happens when a connection is created, but it does not affect which
connections libcurl can reuse. libcurl may reuse a connection that
was set up with a different options string; a different options
string does not by itself prevent reuse. Connection reuse still
depends on other connection properties matching, such as the
protocol, hostname, port number, credentials and other settings that
affect the connection.
DEFAULT
NULL
PROTOCOLS
This functionality affects imap, ldap, pop3 and smtp
EXAMPLE
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode result;
curl_easy_setopt(curl, CURLOPT_URL, "smtp://example.com/");
curl_easy_setopt(curl, CURLOPT_LOGIN_OPTIONS, "AUTH=*");
result = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
HISTORY
Support for OpenLDAP added in 7.82.0.
AVAILABILITY
Added in curl 7.34.0
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).
SEE ALSO
CURLOPT_PASSWORD(3), CURLOPT_USERNAME(3)
libcurl 2026-04-29 CURLOPT_LOGIN_OPTIONS(3)