Re: Identifying Machines

From: Crist Clark (crist.clarkat_private)
Date: Tue Jun 19 2001 - 14:47:45 PDT

  • Next message: Ryan Russell: "Re: Identifying Machines"

    Rick Who Else? wrote:
    > 
    > Let me clarify somewhat. Lets imagine a scenario, of being on a seperate
    > network of your target network. So sniffing traffic and MAC addresses don't
    > apply. And you wish to see how many machines on are a certain subnet. So you
    > wish to scan the entire range of a class C, lets say. ICMP is filtered out.
    > And some of the machines  may have no ports open.
    
    Scanning to see what machines are there should be trivial. A TCP SYN-scan
    (or a variety of more stealthy TCP scans) would do that. More interesting
    TCP scans (X-mas, NULL, surprise-ACK, etc.) can give you more hints about 
    the OS. Of course, once you get any traffic from the hosts, you can also
    look at the IP headers for more clues, TTL, IP ID pattern, DF-bit, etc.
    
    Of course, I am assuming you mean "closed ports" are really closed
    ports (return RSTs when tickled) as opposed to filtered, firewalled
    TCP ports. If that's the case... good luck. 
    -- 
    Crist J. Clark                                Network Security Engineer
    crist.clarkat_private                    Globalstar, L.P.
    (408) 933-4387                                FAX: (408) 933-4926
    
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