topic Re: DHCP issue with Firepower 1010 FTD managed in Network Security

DHCP issue with Firepower 1010 FTD managed

JakeYllus — Thu, 09 Feb 2023 23:47:19 GMT

Good Day All,

I have a simple topology with a Firepower 1010 locally managed. Here what the topo looks like.

I have port 1/1 configured as am access port on a vlan 2 ( outside - internet vlan )

I have port 1/2 as an access port on vlan 1 ( inside )

My DHCP have just a simple pool and configured on the inside interface ( 1/2 )
The inside is connected on a switch on vlan 1 as well .
Users when they try to get IP from the DHCP server on the Firepower are not able to and on top of that the inside interface mac address on a scanner we have internally was showed that all the IP on the pool were assigned to it. ( see the picture bellow ).
All the IP got the same mac which is the inside interface of the firepower.

Any help is appreciated .

Thank you in advance.

Re: DHCP issue with Firepower 1010 FTD managed

balaji.bandi — Wed, 08 Feb 2023 07:12:56 GMT

Thats look blizzard, what is the outcome from command line FTD

what version of FTD, what is the case moving from VLAN 1 to a different VLAN?

>show dhcpd binding all

Re: DHCP issue with Firepower 1010 FTD managed

JakeYllus — Thu, 09 Feb 2023 23:46:01 GMT

Hello,

This was resolved by disabling the arp proxy on the nat rule ( inside , inside ) .

Thank you 🙂

Re: DHCP issue with Firepower 1010 FTD managed

balaji.bandi — Fri, 10 Feb 2023 11:28:31 GMT

Glad to know the resolution and you able to fix the issue.