ping question - TCP-IP

This is a discussion on ping question - TCP-IP ; When I ping power-off machines, sometimes it will return "host not reachable." Sometimes, it will return "request timeout". What is the reason? Thanks...

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  1. ping question

    When I ping power-off machines, sometimes it will return "host not
    reachable." Sometimes, it will return "request timeout".
    What is the reason?

    Thanks



  2. Re: ping question

    In article , a wrote:
    >When I ping power-off machines, sometimes it will return "host not
    >reachable." Sometimes, it will return "request timeout".
    >What is the reason?


    It can depend upon whether the address is still in the ARP caches
    or not.

  3. Re: ping question

    On May 26, 7:23 pm, rober...@hushmail.com (Walter Roberson) wrote:
    > In article , a wrote:
    > >When I ping power-off machines, sometimes it will return "host not
    > >reachable." Sometimes, it will return "request timeout".
    > >What is the reason?

    >
    > It can depend upon whether the address is still in the ARP caches
    > or not.


    ==========================

    I think by using ping command with ip address this make a new entry in
    arp cache in the host pc from where the ping is invoked.

  4. Re: ping question

    In article
    <9ff5ab8e-7400-41ab-9b9d-c7b449e2d019@a32g2000prf.googlegroups.com>,
    vicky wrote:

    > On May 26, 7:23 pm, rober...@hushmail.com (Walter Roberson) wrote:
    > > In article , a wrote:
    > > >When I ping power-off machines, sometimes it will return "host not
    > > >reachable." Sometimes, it will return "request timeout".
    > > >What is the reason?

    > >
    > > It can depend upon whether the address is still in the ARP caches
    > > or not.

    >
    > ==========================
    >
    > I think by using ping command with ip address this make a new entry in
    > arp cache in the host pc from where the ping is invoked.


    It creates an ARP entry, but it will be incomplete until it gets a
    response to the ARP query. If the ARP entry never gets filled in you
    get "Host unreachable".

    --
    Barry Margolin, barmar@alum.mit.edu
    Arlington, MA
    *** PLEASE don't copy me on replies, I'll read them in the group ***

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