Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help 
CURLOPT_SSH_KNOWNHOSTS(3)   Library Functions Manual   CURLOPT_SSH_KNOWNHOSTS(3)

NAME
     CURLOPT_SSH_KNOWNHOSTS - filename holding the SSH known hosts

SYNOPSIS
     #include <curl/curl.h>

     CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSH_KNOWNHOSTS, char *fname);

DESCRIPTION
     Pass  a  pointer  to  a  null-terminated string holding the filename of the
     known_host file to use. The known_hosts file should use  the  OpenSSH  file
     format.  If  this	file is specified, libcurl only accepts connections with
     hosts that are known and present in that file, with a matching public  key.
     Use  CURLOPT_SSH_KEYFUNCTION(3)  to  alter the default behavior on host and
     key matches and mismatches.

     We strongly suggest users doing SCP or SFTP transfers to set this option to
     make sure that the network communication is done with the	intended  server
     and not an impostor.

     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.

     This  option  is  only consulted when libcurl establishes a new connection.
     Once a connection has been created and its host key  verified  against  the
     known  hosts file, it is deemed vetted and may be reused by libcurl without
     re-running the known hosts check, even if you later change SSH host verifi-
     cation options (including	setting  this  option  to  NULL  or  using  CUR-
     LOPT_SSH_HOST_PUBLIC_KEY_SHA256(3)  or CURLOPT_SSH_HOST_PUBLIC_KEY_MD5(3)).
     Such changes only affect subsequently created connections; existing  cached
     connections can continue to be reused with the verification that was in ef-
     fect when they were first established. If you need to force re-verification
     with   the  new  settings,  use  CURLOPT_FRESH_CONNECT(3)	or  CURLOPT_FOR-
     BID_REUSE(3) to avoid reusing the old connection.

DEFAULT
     NULL

PROTOCOLS
     This functionality affects scp and sftp

EXAMPLE
     int main(void)
     {
       CURL *curl = curl_easy_init();
       if(curl) {
	 CURLcode result;
	 curl_easy_setopt(curl, CURLOPT_URL, "sftp://example.com/file");
	 curl_easy_setopt(curl, CURLOPT_SSH_KNOWNHOSTS,
			  "/home/clarkkent/.ssh/known_hosts");
	 result = curl_easy_perform(curl);
	 curl_easy_cleanup(curl);
       }
     }

AVAILABILITY
     Added in curl 7.19.6

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_SSH_AUTH_TYPES(3),     CURLOPT_SSH_HOST_PUBLIC_KEY_MD5(3),     CUR-
     LOPT_SSH_HOST_PUBLIC_KEY_SHA256(3)

libcurl 			   2026-06-11	       CURLOPT_SSH_KNOWNHOSTS(3)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=CURLOPT_SSH_KNOWNHOSTS&sektion=3&manpath=FreeBSD+Ports+15.1.quarterly>

home | help