topic FTD DHCP Server not handing out addresses in Network Security

FTD DHCP Server not handing out addresses

PatrickCavell85782 — Tue, 06 Aug 2024 20:18:04 GMT

We've configured a routed FTD to act as the DHCP server on one interface for guest users. The interface is configured as a 10.100.176.2/23. The DHCP pool for the interface is less than 256 hosts (10.100.176.3 - 10.100.176.254). I understand the pool must be no more than 256 hosts. This a migration from an ASA performing this task. The ASA is configured similarly but it successfully hands out addresses. We do not have have Auto-Configuration checked.

Any thoughts on what we may be doing wrong?

Thanks for any assistance.

Re: FTD DHCP Server not handing out addresses

MHM Cisco World — Tue, 06 Aug 2024 21:02:47 GMT

Check this restrictions of dhcp in ftd

The maximum available DHCP pool is 256 addresses.
You can configure only one DHCP server on each interface. Each interface can have its own pool of addresses to use. However the other DHCP settings, such as DNS servers, domain name, options, ping timeout, and WINS servers, are configured globally and used by the DHCP server on all interfaces.
You cannot configure an interface as a DHCP client if that interface also has DHCP server enabled; you must use a static IP address.
You cannot configure both a DHCP server and DHCP relay on the same device, even if you want to enable them on different interfaces; you can only configure one type of service.
FTD device does not support QIP DHCP servers for use with the DHCP proxy service.
The DHCP server does not support BOOTP requests.

Re: FTD DHCP Server not handing out addresses

PatrickCavell85782 — Tue, 06 Aug 2024 21:06:05 GMT

I don't think we're violating any of these restrictions.

Re: FTD DHCP Server not handing out addresses

MHM Cisco World — Tue, 06 Aug 2024 21:12:46 GMT

You cannot configure both a DHCP server and DHCP relay on the same device

Are you sure you not run both relay and server?

MHM

Re: FTD DHCP Server not handing out addresses

PatrickCavell85782 — Wed, 07 Aug 2024 01:48:09 GMT

You may be right. I will check with my customer to see if they do indeed have DHCP Relay already configured. Thanks!

Re: FTD DHCP Server not handing out addresses

PatrickCavell85782 — Wed, 07 Aug 2024 16:19:28 GMT

Problem solved. Changed the FTD interface from a /23 to a /24 and DHCP server start handing out addresses.

Re: FTD DHCP Server not handing out addresses

MHM Cisco World — Wed, 07 Aug 2024 16:25:01 GMT

Thanks for update me

Have a nice summer

MHM