DHCP access

Marty Landman MLandman at face2interface.com
Sun Feb 22 10:55:28 PST 2004

At 12:01 PM 2/22/2004, Olaf Hoyer wrote:

>Well, what is formerly called a "Class C" network is now in the new 
>CIDR-notation a "/24", meaning that there are 256 IP's in that network.

Thanks for explaining Olaf. Little by little the fog is clearing before my 
eyes, and things which are just words to me today will likely make real 
sense in a month or whatever it takes.

>Seems to be a bug with nmap V3.00 I use 3.50, and it works. Solution could 
>be an upgrade or exclusion of your own box from the scanning range.

Could you explain how I can do either - or preferably both? My experience 
with ports btw is strictly limited to

make build && make install

>Ok, some basics beforehand:
>anytime some hosts wants to contact another host, it yells with some 
>broadcast on the local collision segment (arp-request) that the Station, 
>which has IP-address a.b.c.d. sprays the answer (the MAC-Address on the 
>other station) back throughout the segment. This answer is cached by the 
>OS for a short time, that for future use no unnecessary lookups have to be 


>This means, that, if you hook up a station to a LAN, which did not 
>participiated in any of the LAN traffic, the arp cache on that station is 
>of course empty.

So the arp cache doesn't have nodes on it which it hasn't had activity from 
for a time? This makes sense since I tend to work off my windows 
workstation which is also my gateway.

>One way to fill it, is by simply pinging all other hosts on that segment.

Heh, heh. That's really how this started, except I found it to be too time 
consuming to do so.

Maybe I'm getting far afield though. I think what I'm looking to do now is 
schedule an exec through cron which will check for whatever ip's/hostnames 
are on my network. Sounds like upgrading nmap to 3.50 will do it.

Marty Landman   Face 2 Interface Inc 845-679-9387
This Month's New Quiz --- Past Superbowl Winners
Make a Website: http://face2interface.com/Home/Demo.shtml

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