CURLOPT_SSL_VERIFYHOST - verify the certificate's name against host
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_VERIFYHOST, long verify);
Pass a long as parameter specifying what to verify
This option determines whether libcurl verifies that the server cert is for the
server it is known as.
When negotiating TLS and SSL connections, the server sends a certificate
indicating its identity.
is 2, that certificate must indicate that
the server is the server to which you meant to connect, or the connection
fails. Simply put, it means it has to have the same name in the certificate as
is in the URL you operate against.
Curl considers the server the intended one when the Common Name field or a
Subject Alternate Name field in the certificate matches the host name in the
URL to which you told Curl to connect.
When the verify
value is 1, curl_easy_setopt
will return an error
and the option value will not be changed. It was previously (in 7.28.0 and
earlier) a debug option of some sorts, but it is no longer supported due to
frequently leading to programmer mistakes. Future versions will stop returning
an error for 1 and just treat 1 and 2 the same.
When the verify
value is 0, the connection succeeds regardless of the
names in the certificate. Use that ability with caution!
The default value for this option is 2.
This option controls checking the server's certificate's claimed identity. The
server could be lying. To control lying, see CURLOPT_SSL_VERIFYPEER(3)
DarwinSSL: If verify
value is 0, then SNI is also disabled. SNI is a TLS
extension that sends the hostname to the server. The server may use that
information to do such things as sending back a specific certificate for the
hostname, or forwarding the request to a specific origin server. Some
hostnames may be inaccessible if SNI is not sent.
NSS: If CURLOPT_SSL_VERIFYPEER(3)
is also set to zero and cannot be overridden.
All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
CURL *curl = curl_easy_init();
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
/* Set the default value: strict name check please */
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 2L);
If built TLS enabled.
Returns CURLE_OK if TLS is supported, and CURLE_UNKNOWN_OPTION if not.
If 1 is set as argument, CURLE_BAD_FUNCTION_ARGUMENT