Hi, I've been looking at handling host keys better, and tripped over this bug. Essentially, if the server offers a HostCertificate that the client doesn't accept, then the client doesn't then check for SSHFP records. Setup to reproduce: Server has a HostCertificate, and appropriate SSHFP entries in the DNS. Client does /not/ have a @cert-authority entry in known_hosts What should happen: Server offers the certificate, client rejects it and then validates the SSHFP entry, and goes on to connect. What does happen: Server offers the certificate, client rejects it and then falls back to prompting the user. You can work around this by doing -o 'HostKeyAlgorithms=ssh-rsa', but that disables certificate checking entirely, so isn't actually a fix. I think this is a security issue, as host key checking is IMO important security-wise, but I think "important" is the correct severity. Regards, Matthew -- System Information: Debian Release: 7.4 APT prefers stable-updates APT policy: (500, 'stable-updates'), (500, 'stable'), (1, 'experimental') Architecture: amd64 (x86_64) Kernel: Linux 3.2.0-4-amd64 (SMP w/8 CPU cores) Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Versions of packages openssh-client depends on: ii adduser 3.113+nmu3 ii debconf [debconf-2.0] 1.5.49 ii dpkg 1.16.12 ii libc6 2.13-38+deb7u1 ii libedit2 2.11-20080614-5 ii libgssapi-krb5-2 1.10.1+dfsg-5+deb7u1 ii libselinux1 2.1.9-5 ii libssl1.0.0 1.0.1e-2+deb7u4 ii passwd 1:4.1.5.1-1 ii zlib1g 1:1.2.7.dfsg-13 Versions of packages openssh-client recommends: ii openssh-blacklist 0.4.1+nmu1 ii openssh-blacklist-extra 0.4.1+nmu1 ii xauth 1:1.0.7-1 Versions of packages openssh-client suggests: pn keychain <none> pn libpam-ssh <none> pn monkeysphere <none> pn ssh-askpass <none> -- Configuration Files: /etc/ssh/ssh_config changed: Host * SendEnv LANG LC_* HashKnownHosts yes GSSAPIAuthentication yes GSSAPIDelegateCredentials no -- no debconf information