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Ian_Støttrup's avatar
Ian_Støttrup
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Sep 19, 2017

SSH-proxy and keyboard interactive authentication not working

I am trying to test the SSH proxy funtionality of AFM, but I am not succeeding at all. I am aiming for keyboard interactive authentication (username/password), but all I get is "Authentication failed."

For my test-setup I have followed this to the letter: https://support.f5.com/kb/en-us/products/big-ip-afm/manuals/product/network-firewall-policies-implementations-12-1-0/13.print.html Section: Defining SSH proxy password or keyboard interactive authentication

My setup goes: 10.128.1.1 --> 10.128.10.100 (VS with SSH-proxy profile) --> 10.128.10.128 (backend server)

Directly SSH 10.128.1.1 ---> 10.128.10.128 work just fine If I goes through the virtuel Bigip on 10.128.10.100 I get:

debug1: Host '10.128.10.100' is known and matches the RSA host key.
debug1: Found key in /Users/testuser/.ssh/known_hosts:4
debug1: rekey after 4294967296 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey after 4294967296 blocks
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,keyboard-interactive,password
debug1: Next authentication method: publickey
debug1: Trying private key: /Users/testuser/.ssh/id_rsa
debug1: Trying private key: /Users/testuser/.ssh/id_dsa
debug1: Trying private key: /Users/testuser/.ssh/id_ecdsa
debug1: Trying private key: /Users/testuser/.ssh/id_ed25519
debug1: Next authentication method: keyboard-interactive
Authentication failed.

I have taken to public key from the backend server /etc/ssh/ssh_host_rsa_key.pub and placed a copy in "Real Server Auth Public Key" field.

I have taken a private key generated on the virtual Bigip, using ssh-keygen, and placed a copy in "Proxy Server Auth Private key" field.

I made sure that HostKey /etc/ssh/ssh_host_rsa_key is not commented out on the backend server.

According to the article linked to above, it should now work, but it does not. Can anyone help me?

AFM
keyboard interactive authentication
LTM
security
ssh

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  • Ian_Støttrup's avatar
    Ian_Støttrup
    Icon for Nimbostratus rankNimbostratus
    Sep 20, 2017

    I believe I got it working now. Instead of using the public key on the backend server placed in /etc/ssh/ssh_host_rsa_key.pub, I used the public key that was in my clients .ssh/known_hosts, after having connected directly to 10.128.10.128. This key I placed in the Real Server Auth Public Key field and now I can log in, through the Bigip, using username/password and SCP is not allowed through, which was my goal.