CURLOPT_SSH_KNOWNHOSTS - filename holding the SSH known hosts

Added in curl 7.19.6

NULL

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.

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

CURLOPT_SSH_KNOWNHOSTS - filename holding the SSH known hosts

This functionality affects scp and sftp

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).

CURLOPT_SSH_AUTH_TYPES(3), CURLOPT_SSH_HOST_PUBLIC_KEY_MD5(3), CURLOPT_SSH_HOST_PUBLIC_KEY_SHA256(3) libcurl 2025-06-16 CURLOPT_SSH_KNOWNHOSTS(3)

#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSH_KNOWNHOSTS, char *fname);