I’m busy with a Node.js project at work. The project requires SFTP support and for that we decided to use the ftps module. Although I was able
to connect to the SFTP server using lftp and FileZilla without any problems, the Node.js project was failing. By checking the logs of the project I noticed that the cause was the infamous “Host key verification failed” problem.
Since SFTP uses SSH, it requires an initial key exchange between the client (in this case, my computer) and the server. Apparently the ftps Node
module cannot deal with this key exchange. One solution is to force this procedure using the classic ssh command. Even if the SFTP server is
configured not to allow remote shell connections (usually it connects to nologin or false), it will do the job.
So, if you are using SFTP in your software project and you are dealing with host key verification failures, try connecting to the server using an SSH client first.