Releases and Monitoring

Randall C Grimshaw rgrimsha at
Wed Jul 25 20:20:34 UTC 2007

You cannot disconnect the clients lease, but you can add the mac to a
class you might call 'quarantine' and then have a deny members of
'quarantine' rule for each of the relevant pools.

You can log to syslog and even log detailed data on the commit event.


-----Original Message-----
From: dhcp-users-bounce at [mailto:dhcp-users-bounce at] On
Behalf Of Nathan Michaels
Sent: Wednesday, July 25, 2007 1:23 PM
To: dhcp-users at
Subject: Releases and Monitoring

I'll explain my situation first, then get on with the questioning.
A single DHCP server (running on Linux) is going to be used for a pretty
large (10,000+ clients) network. There may be more DHCP servers in the
future for load handling, but this is how it will be to start. Our
systems (clients) all have similar (regex-able) MACs, but they're not
the only systems that will use the DHCP server. They're also going to
have infinite leases on their addresses. This brings me to the first
question. Is there a way to, if I know the MAC of the unit I'm pulling
off the network, tell the server directly to release that MAC's lease?

Secondly, I'd like to be able to see when our units join the network. Is
there a way to do that short of tailing the dhcpd.leases file? Ideally,
I'm looking for a setting where if a MAC requesting a lease matches a
regex the server will run a program. I don't want to be constantly
monitoring the dhcpd.leases file because of all the other unrelated
traffic I'd have to filter out.

I don't need to be able to actually do these things myself right now,
just know if they can be done. That said, any pointing in the right
direction for how to do them would be much appreciated.


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