Re: Re: Finding IP Devices on a LAN?

[Jewelie <jewelie@xxxxxxxxx>]

On Fri, May 16, 2008 at 4:03 PM, dermot_bradley
<bradley@xxxxxxx> wrote:
> If all the 22 devices are running TCP/IP then it is strange that 14 of
> them weren't detected. Maybe these devices have an incorrectly
> configured netmask/broadcast address or else you didn't ping the
> correct broadcast address (x.x.x.255 only applies for a /24 network).

Or devices that don't respond to a ping. Quite often devices don't do
so, or can be configured not to. Same for servers. Why broadcast that
something exists when you don't have to ?

There even exists system that only appear when you send a sequence of
packets to it, either a single specially formed packet, or a series of
them to different ports. They appear to do to nowhere until the
sequence is complete, then the server opens up a port to the IP
address that send the sequnce. Think it is called port knocking, but
read about one that does it to one port/address rather than a sequnce
and encrypts the data send to validate who the sender is so it can't
be spoofed.

Julie

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