topic Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400 in Firewall and Security Management

Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

marius_kade — Thu, 01 Feb 2024 16:30:29 GMT

Hello everyone,

Our CheckPoint Cluster manages DHCP in some of our networks. I'm trying to ensure that a specific device always gets the same IP address, and I'd like to achieve this through DHCP reservation or another option.

Despite searching online and in the forum, I haven't been able to find a solution. Does anyone now how to do this on a CheckPoint 6400 Base Cluster?

Thanks for your assistance,
Marius

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

PhoneBoy — Fri, 02 Feb 2024 03:52:10 GMT

Requires editing a configuration file.
See: https://support.checkpoint.com/results/sk/sk92473

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

marius_kade — Fri, 02 Feb 2024 07:30:49 GMT

Thanks for your reply.

So as i understand right, i have to write it like the example below in the dhcpd.conf file right?
Do have to this on both cluster members?

Can i use the IP-address of the lease that the client already has or do i have to pick a not assigned one?

Example:

________________________________________________________________

ddns-update-style none;

subnet 192.168.89.0 netmask 255.255.255.0 {

default-lease-time 43200;

max-lease-time 86400;

option host-name= pick(option host-name,

concat("dhcp-", binary-to-ascii(10, 8, "-", leased-address)));

range 192.168.89.10 192.168.89.254;

option routers 192.168.89.1;

option domain-name-servers 9.9.9.9, 1.1.1.1;

}

host testclient {

hardware ethernet 08:50:40:A2:F2:3D

fixed-address 192.168.89.20

}

________________________________________________________________

Thanks for your help!!!

Marius

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

marius_kade — Tue, 06 Feb 2024 13:59:27 GMT

Thank you for your response!

Sorry for my late response, but I had already written something, but it either disappeared or never appeared.

So, does that mean I have to enter it in the dhcpd.conf file, right?
Should I do that on both cluster members? Or maybe even on the management server?
Is this syntax correct?

Config example:

ddns-update-style none;

subnet 192.168.89.0 netmask 255.255.255.0 {

default-lease-time 43200;

max-lease-time 86400;

option host-name= pick(option host-name,

concat("dhcp-", binary-to-ascii(10, 8, "-", leased-address)));

range 192.168.89.10 192.168.89.254;

option routers 192.168.89.1;

option domain-name-servers 9.9.9.9, 1.1.1.1;

}

host testclient {

hardware ethernet 08:50:40:A2:F2:3D

fixed-address 192.168.89.20

}

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

PhoneBoy — Tue, 06 Feb 2024 19:29:06 GMT

Yes, it needs to be entered on both cluster members and it may require a restart of dhcpd.
I believe the main thing to be entered is the host testclient stanza (each line needs a semicolon at the end).

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

marius_kade — Tue, 13 Feb 2024 09:59:21 GMT

Many Thanks! I will try it.

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

martin-mandat — Wed, 10 Jul 2024 06:54:00 GMT

Be aware that any changes directly made in /etc/dhcpd.conf will be lost after gateway reboot or restart of network services because management process on gateway creates fresh dhcpd.conf based on information in configuration.

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

PhoneBoy — Wed, 10 Jul 2024 17:43:22 GMT

You have to make file immutable per: https://support.checkpoint.com/results/sk/sk92473

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

MTFT — Mon, 19 Jan 2026 04:54:09 GMT

As someone who apparently doesn't have access to that article, could you elaborate on how this is done?

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

_Val_ — Mon, 19 Jan 2026 08:01:04 GMT

You need to log in to the UserCenter to see it. If you are logged in to CheckMates, you should be able to log in there as well.

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

PhoneBoy — Mon, 19 Jan 2026 19:27:05 GMT

The actual command is a standard Linux (expert mode) command: chattr +i /etc/dhcpd.conf
The SK (which requires you to be logged in to see) is merely a reference that it's required in this case.

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

AttiqRahman786 — Tue, 20 Jan 2026 09:48:12 GMT

A while back, I created a document explaining the process in detail. It works for me. hope it helps.

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

MTFT — Wed, 21 Jan 2026 23:08:39 GMT

Thanks! I figured it was that or something similar but wanted to make sure.
I did try looking at that SK while logged in bit still was unable to access it, seems that you need to have some higher level of access than I do.

Re: Setting an DHCP Reservation in CheckPoint DHCP Server on 6400

PhoneBoy — Thu, 22 Jan 2026 16:35:52 GMT

Some SK articles require your UserCenter account to be tied to an active support agreement.