CURLOPT_SASL_IR(3) Introduction to Library Functions CURLOPT_SASL_IR(3)

NAME

CURLOPT_SASL_IR - send initial response in first packet

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SASL_IR, long enable);

DESCRIPTION

Pass a long. If the value is 1, curl sends the initial response to
the server in the first authentication packet in order to reduce the
number of ping pong requests. Only applicable to the following
supporting SASL authentication mechanisms:

* Login * Plain * GSSAPI * NTLM * OAuth 2.0

Note: Whilst IMAP supports this option there is no need to explicitly
set it, as libcurl can determine the feature itself when the server
supports the SASL-IR CAPABILITY.

DEFAULT

0

PROTOCOLS

This functionality affects imap 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_SASL_IR, 1L);
result = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}

AVAILABILITY

Added in curl 7.31.0

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_MAIL_AUTH(3), CURLOPT_MAIL_FROM(3), CURLOPT_SASL_AUTHZID(3)

libcurl 2026-01-08 CURLOPT_SASL_IR(3)