Failover and number of IP reserved for failover by DHCP servers.

[Luis Fernando Lacayo]

HI all, 

If I am understanding the way that DHCP does failover/redundancy
correctly, each server will hold on to a set of IP's that it will assign
in case the communications link is lost between the two servers.  

I have a perl program that lists the number of IP's in a scope the
results look like this:

Size, Used, High, Abandon, %Full, Subnet, Subnet Name 

722     321     321     131     44%     10.43.48.0         XXXXXXXXX 
210     86         86         2     40%     10.116.224.0     XXXXXXXX
ADMIN 

so for the admin network, it shows that there are 86 ip's used but we
know for a fact that only 6 are in used.  So I am thinking that each of
the servers is holding 20% of the available IPs.  

So I am running into a problem, when I have a small network,  we reserve
the 19 for district use and the last last 24 for local servers and
printers. in a /24 network my scope will be  10.116.224.21 to
10.116.224.230 - 210 but the servers must reserve 40 each which bring me
down to 130. I have a 4 day lease on the IP's so I frequently run out of
IP's, I can lower the lease (Already did it to half the time) but I
would like to know if there is a way to reduce the number of IP that is
reserved by each server. 

thanks in advance. 

Luis
-- 
Luis Fernando Lacayo
Chicago Public Schools
Senior Unix Administrator
ITS/ UNIX Infrastructure
Office: 773-553-3835
Cell: 773-203-4493
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