How to sync DHCP lease information between cluster members?

[Sung]

Hello,

Platform: 3600
Version: R81

I configure DHCP server with same IP range in HA cluster, but it seems that DHCP lease information did not sync.
In my test, once active gateway goes down, backup gateway will be active and offer the dupulicate IP to clients.
Is it possbile to sync lease information by execute CLI command/upgrade gateway to latest version...etc so that we can use the same IP range.

One more thing is that I am curious if SMB model has the same behavior.
Does anyone knows if they are using the same DHCP solution/mechanism?
It is because I did not get the dupulicate IP when I do the same test to 1550 with R80.20.

Thanks,

[PhoneBoy · Accepted solution]

There is no built-in mechanism that will sync DHCP information between cluster members.
See: https://support.checkpoint.com/results/sk/sk42308
It's possible the SMB appliances handle this better since the clustering/DHCP mechanisms are a little different.

[Paul_Warnagiris]

What's going on Checkmates?  I just had what I thought was an odd question and it led me here.  My customer asked me if DHCP is stateful and the question is no, but then they told me they "should" configure a different range on each cluster member.  I have never done this in this fashion.  I always configured the same range (admittedly I don't do it often) on both cluster members.  But he pointed me to this Checkmates link 

https://community.checkpoint.com/t5/Security-Gateways/DHCP-server-config-clusterXL-sync-leases/td-p/... where it seems to indicate "you can have two different ranges."  What is the best practice (other than to use a real DHCP server 😃 ).  Configure two different ranges or to configure the same range?  Either way the clients will lose connectivity, but wondering what the feedback may be from the community.

Thanks in advance!

[PhoneBoy]

In practice, I’ve never heard of issues with configuring the same DHCP range on both.