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 doesn't.
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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're   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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