Resyncing ISC DHCP Servers?

mrm5102 · 01-26-2018, 02:43 PM

Hello All,

Code:

# dhcpcd --version
dhcpcd 3.2.3
Compile time options: ARP INFO IPV4LL NIS NTP SYSV RESOLVCONF

We currently have 2 of these DHCP servers running in our Network. About 2 weeks ago there was an outage in our Failover location and after the location came back up the following day we were having some IP Addressing issues. So my boss dissabled the DHCP services on the Failover server, which fixed the issue at that time.

I am wanting to re-enable to dhcpd service on the Failover server, and I'm wondering if there are any steps that need to be done before I re-enable dhcpd on the failover server.?

*For Example:
I assume we need to copy the /etc/dhcpd.conf.d/dhcpd.server.config File (*which contains the Pools and and Static Host assignments) from the Primary server over to the failover server before we turn the service back on?
Do we need to clear out the /var/lib/dhcp/db/dhcpd.leases file on the failover server?
Etc.....?

If anyone knows the steps for this scenario, it would be greatly appreciated!

Thanks in Advance,
Matt

lazydog · 01-27-2018, 09:37 AM

You cannot just copy over the file as each file is unique to the server itself that lets it know if it is the primary or secondary server.
I would compare the 2 and add/remove what is different between the two. Looking at the keys and pools to ensure they are the same.

mrm5102 · 01-29-2018, 12:58 PM

Hey, thanks for the reply, and sorry for the delay.

Right. I meant for the config file containing the DHCP Pools and Static hosts. Which for us, it's located here:

Code:

/etc/dhcpd.conf.d/dhcpd.server.config

.
The file containing the DHCP Server Primary and Failover Addresses and Ports is located here:

Code:

/var/lib/dhcp/etc/dhcpd.conf

.
So I was assuming I'd need to copy the dhcpd.server.config file to the failover server, since a few static hosts have been added since the Failover server was temporarily disabled. And, possibly delete these 2 files below from the Failover Server..?

Code:

/var/lib/dhcp/db/dhcpd.leases
/var/lib/dhcp/db/dhcpd.leases~

Thanks AGain,
Matt