[olug] DHCP rollout

[David Walker]

I run arpwatch as a security measure and it isn't going to do anything you 
aren't doing already.  arpwatch is only going to help if you do the pinging 
as you are already doing.

Why do you need new machines to go into the old /24?  It seems to me that you 
have plenty of new addresses in the /16 network that you can just block the 
/24 from the dhcp settings and have no conflicts.

On Thursday 03 July 2003 02:52 pm, Eric Penne wrote:
> As some of you know, the company I work for is having IP address problems
> (not enough), and they don't have a DHCP server to help with the change
> from a /24 network to a /16 network.  The Cisco 675 router is also dealing
> them fits but it is being replaced in the next week or two.
>
> I'm proposing we set up a DHCP server with the current IP addresses
> reserved so the DHCP server doesn't walk all over them when a new PC gets
> connected.  I wrote a script that pings all the addresses on our /24 then
> grabs the MAC address from /proc/net/arp.  I'm hoping that by doing this I
> can create a DHCP config with these MACs and IPs being protected (roughly
> DHCP'd static IPs).  I've already done the leg work and anybody that wants
> the script is more than welcome to it.
>
> Is there a better way to do it?  I've looked at arpwatch but it didn't
> seem to work very well for me.  I thought it was because I'm on a switched
> network.  My scripting approach seems to be more proactive about getting
> the MACs than arpwatch since I actively ping the machines.
>
> Most machines are off today since the plant is in a "slow down" period.
> I'll have to run this script regularly during the different shifts and
> over a few days to try to catch vacationing office workers and transient
> PCs out in the plant.
>
> Later
> Eric Penne
>
>
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