Help me!!!

Discussion in 'other security issues & news' started by tigerme, Nov 3, 2003.

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  1. tigerme

    tigerme Registered Member

    Nov 2, 2003
    I have a question here.

    1. use ping to a host which has already benn shutdown
    2. use ping to a host with a firewall that filtering icmp packet

    Are the results of the above 2 cases identical?
    if there are identical, how can i affirm that a certain host is shutdown.

    Help me please!!!!! o_O
  2. LowWaterMark

    LowWaterMark Administrator

    Aug 10, 2002
    New England
    Someone who understands networking at the detail level and who can interpret the RFCs involved, one of which is this one rfc792, could much better explain this I'm sure. The best I can do is mention a few things I think are true based upon some observations and some reading (so techs please excuse me for some incorrect technical terminology :rolleyes: )...

    I believe the original intent was that the gateway to the host being pinged would return a host or destination unreachable message to the source, (the host issuing the ping), if the destination host was unavailable. (A rather useful service, I believe.) But with all the changes, hacks and stealthing going on today on the Internet, I don't think you can count on this any longer. Especially given the more dramatic changes (restrictions) the network providers have been implementing lately to combat all the silly worm related network traffic.

    So, I would guess that whether you get some form of unreachable message or not, given what's going on today, is pretty much a flip of a coin. I don't think you can rely on it in all situations in order to figure out if a host is really there or not.
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