migrate from remotely located to central servers

Jason Brooks jasonbbrooks at gmail.com
Wed Jul 29 16:35:26 UTC 2020


I am having trouble relocating and upgrading a number of dhcp servers.  I
am upgrading from solaris running dhcpd 3.0.4 to centos 7's dhcp 4.2.5-77.

The problem: when I test the config on the new dhcp servers, I get the
following error: "No free leases".

As I am still testing, I have not copied the leases thus it is not clear
why there would be no free leases.

As I have no lab equipment to test against,  I am generating similar
queries using the dhtest
I started with a packet capture on the live dhcp servers and constructed a
dhcp discovery packet based on it.  I have also started small, with the
smallest configuration possible that should still work.

The queries originate from DSL customer premises equipment (CPE), and are
forwarded by a dsl shelf manager.  The relevant fields in the forwarded
queries are as follows:
giaddr: <management ip of dsl shelf>  (Please note this is NOT the ip
address facing the CPE)
chaddr: <mac of CPE>
option 82.1: circuit id
option 82.2: remote id
option 60: vendor class identifier (only on boot and management classes)

The current live system is running 8 pairs of dhcp servers in different
regions.  They have been successfully running for more than 8 years.  At
last count there are about 440,000 active leases.

I am attempting to build a pair of centrally located servers.  I am not
trying to do HA yet.

I am including a sanitized dhcpd.conf file for you to look at.

Thank you all for your time!

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