DHCP Failover and DHCP relay question
Darren
perl-list at network1.net
Mon Mar 27 21:24:29 UTC 2006
Mr. Hankins (or anyone who knows the answer to this question),
v.3.0.3 of ISC DHCP
Lets say we have DHCP failover partners at 192.168.0.1 and 192.168.0.2
and a cable modem bootp server running on windows at 192.168.0.3 for
example. The client DHCP of a cable modem network will be going to the
DHCP failover partners. The cable modem bootp traffic will be going to
the windows bootp server. It is not possible in this example to place
the bootp on the failover partners (actually, I don't think the ISC DHCP
server supports bootp on failover anyways).
We have an old USR cable access router that will be acting as the DHCP
relay agent for both cable modems and the clients behind them. While
this router does support failover, it does not support separation of the
client/cable modem traffic. Therefore, to make this work we would set
the primary DHCP server on the cable access router to 192.168.0.3 so
that the cable modem bootp traffic goes to the windows server. We will
set the secondary DHCP server to 192.168.0.1 so that the client DHCP
goes to the first failover server.
Can anyone tell me if this will work? Specifically, what will happen if
the hash check on the client MAC Address says that the secondary DHCP
server should answer, but the secondary server never received the DHCP
Discover message from the client? Will the primary client answer? If
so, what parameters will determine if it answers (IE, what should these
options be set too:
max-response-delay 5;
max-unacked-updates 5;
mclt 600;
split 128;
load balance max seconds 5;
This failover cluster will also be used by other DHCP Relay agents that
do indeed support failover properly, and many of which are not cable
modem networks at all.
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