CURLOPT_DOH_SSL_VERIFYPEER(3)

1CURLOPT_DOH_SSL_VERIFYPEER(3c)url_easy_setopt optionCsURLOPT_DOH_SSL_VERIFYPEER(3)
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NAME

6       CURLOPT_DOH_SSL_VERIFYPEER - verify the DoH SSL certificate
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SYNOPSIS

9       #include <curl/curl.h>
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11       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DOH_SSL_VERIFYPEER,
12                                 long verify);
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DESCRIPTION

15       Pass a long as parameter set to 1L to enable or 0L to disable.
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17       This option tells curl to verify the authenticity of the DoH (DNS-over-
18       HTTPS) server's certificate. A value of 1 means curl verifies; 0 (zero)
19       means it does not.
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21       This option is the DoH equivalent of CURLOPT_SSL_VERIFYPEER(3) and only
22       affects requests to the DoH server.
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24       When negotiating a TLS or SSL connection, the server sends  a  certifi‐
25       cate  indicating its identity. Curl verifies whether the certificate is
26       authentic, i.e. that you can trust that the server is who the  certifi‐
27       cate says it is.  This trust is based on a chain of digital signatures,
28       rooted in certification authority (CA) certificates you  supply.   curl
29       uses  a  default bundle of CA certificates (the path for that is deter‐
30       mined at build time) and you can specify  alternate  certificates  with
31       the CURLOPT_CAINFO(3) option or the CURLOPT_CAPATH(3) option.
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33       When  CURLOPT_DOH_SSL_VERIFYPEER(3)  is  enabled,  and the verification
34       fails to prove that the certificate is authentic, the connection fails.
35       When the option is zero, the peer certificate verification succeeds re‐
36       gardless.
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38       Authenticating the certificate is not  enough  to  be  sure  about  the
39       server. You typically also want to ensure that the server is the server
40       you mean to be talking to.  Use CURLOPT_DOH_SSL_VERIFYHOST(3) for that.
41       The  check  that the host name in the certificate is valid for the host
42       name  you  are  connecting  to  is  done  independently  of  the   CUR‐
43       LOPT_DOH_SSL_VERIFYPEER(3) option.
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45       WARNING:  disabling  verification of the certificate allows bad guys to
46       man-in-the-middle the communication without you knowing  it.  Disabling
47       verification  makes  the communication insecure. Just having encryption
48       on a transfer is not enough as you cannot be sure that you are communi‐
49       cating with the correct end-point.
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DEFAULT

52       1
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PROTOCOLS

55       DoH
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EXAMPLE

58       CURL *curl = curl_easy_init();
59       if(curl) {
60         curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
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62         curl_easy_setopt(curl, CURLOPT_DOH_URL, "https://cloudflare-dns.com/dns-query");
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64         /* Disable certificate verification of the DoH server */
65         curl_easy_setopt(curl, CURLOPT_DOH_SSL_VERIFYPEER, 0L);
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67         curl_easy_perform(curl);
68       }
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AVAILABILITY

71       Added in 7.76.0
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73       If built TLS enabled.
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RETURN VALUE

76       Returns  CURLE_OK  if the option is supported, and CURLE_UNKNOWN_OPTION
77       if not.
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