Re: SSHD and SSH Call-out via Port Knocking

From: Johan De Meersman (jdm_at_operamail.com)
Date: 09/07/05

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    Date: Wed, 07 Sep 2005 11:06:09 +0200
To: guyverdh@mchsi.com

    guyverdh@mchsi.com wrote:

    >Both versions use a series of scripts to write numerals into a temporary file via knocks on specific ports. This file is then read when one of two ports are knocked after having 12 digits written to the file.
    >
    >
    expand on this, please - what are those 12 digits, where do you get them
    from, ... ?

    >One port, reads the temporary file, builds the IP address, then creates an iptables entry that allows the specified IP address to connect via SSH for approximately 30 seconds. It then closes the SSHD daemon, and drops the iptables entry.
    >
    >
    Standard port knocking, well documented. What's the use of the tempfile ?

    >The second port, reads the temporary file, builds the IP address, then causes SSH to connect to the specified IP address with a backchannel defined. This allows the remote client to ssh into the server via this backchannel.
    >
    >
    If I understand this correctly, you're going to tunnel an SSH connection
    over another SSH connection ? Why ? 

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