RE: Bypassing firewall

From: Marcus J. Ranum (mjrat_private)
Date: Tue Feb 01 2000 - 19:18:36 PST

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    >Youre example is not using a proxy based firewall, you are using the
    >transparent DNS port. If you force the DNS through a proxy proces as it
    >should on a proxy based firewall (hidden DNS o.i.d) (No transparent
    >connection at all) then this trick will not work.
    
    
    Back when I was writing the firewall toolkit I hacked together a
    version of a /dev/tun driver and had it piping its output into a
    script that uuencoded packets, then emailed them to an alias on
    a remote machine which uudecoded them and shoved them into /dev/tun.
    It worked; ping round trip times were in the order of seconds,
    which made running NFS difficult without adjusting timeouts. I
    was able to mount filesystems after a bit of fiddling, and could
    get a very slow telnet session connected.
    
    Tunnelling over DNS would be silly, anyhow; most firewalls
    have this huge gaping hole called SSL...
    
    mjr.
    



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