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Date:      Tue, 24 Mar 2009 10:11:37 +0000
From:      Bruce Cran <bruce@cran.org.uk>
To:        perryh@pluto.rain.com
Cc:        jalmberg@identry.com, freebsd-questions@freebsd.org
Subject:   Re: utility that scans lan for client?
Message-ID:  <20090324101137.GB451@muon.cran.org.uk>
In-Reply-To: <49c88f26.l1EpVEWeSl4QsOWV%perryh@pluto.rain.com>
References:  <E4A3989A-982F-4B9D-971D-25C49A932EB7@identry.com> <200903232010.21179.mel.flynn+fbsd.questions@mailing.thruhere.net> <49c88f26.l1EpVEWeSl4QsOWV%perryh@pluto.rain.com>

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On Tue, Mar 24, 2009 at 12:43:34AM -0700, perryh@pluto.rain.com wrote:
> Mel Flynn <mel.flynn+fbsd.questions@mailing.thruhere.net> wrote:
> > On Monday 23 March 2009 19:59:36 John Almberg wrote:
> > > What I'm looking for is a utility that can scan a LAN for attached
> > > clients... i.e., computers that are attached to the LAN.
> > >
> > > I have one box (an appliance that I have no access to), that is on
> > > the LAN but I don't know what IP address it's using. I'd like to
> > > complete my network map, and that is the one empty box on my chart.
> >
> > security/nmap
> >
> > If the box pings, you can simply scan your LAN like:
> > $ nmap -sP 192.168.2.0/24
> 
> Or, with no ports needed:
> 
> $ ping -n -t 5 -i 10 192.168.200.255
> 
> Granted you need to know the broadcast address.  If you know the
> interface name, you can get the broadcast address from ifconfig:

That only works if the OS is configured to reply to broadcast ping,
which appears to be usually disabled nowadays. At least on FreeBSD 7.1
net.inet.icmp.bmcastecho defaults to 0.

-- 
Bruce Cran



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