topic DHCPD issue with Firepower 7.0.1-7.1.0 in Network Security

DHCPD issue with Firepower 7.0.1-7.1.0

babiojd01 — Thu, 07 Apr 2022 00:26:44 GMT

So i have been deploying cisco FDM managed firewalls. I noticed an interesting bug with DHCP and 7.x code. If install a config via a backup, configure via API and upload a config, or deploy a template to a 7.x code using CDO to the firewall it botches DHCP. Clients will run through the entire scope and request every IP address. Its a constant DHCP Decline via wireshark. Has any else seen this? I can duplicate it and have. If i stick with 6.6 code it seems to work.

Re: DHCPD issue with Firepower 7.0.1-7.1.0

balaji.bandi — Thu, 07 Apr 2022 06:34:19 GMT

personally, i will not use FW as DHCP Server, but sometimes requirements may change.

Since this is new code, there may be bugs around worth looking at below release notes :

https://www.cisco.com/c/en/us/td/docs/security/firepower/70/relnotes/firepower-release-notes-700/bugs.html

if this is a major issue worth contacting Cisco TAC.

Re: DHCPD issue with Firepower 7.0.1-7.1.0

john_atKeystonetec — Fri, 08 Apr 2022 00:39:46 GMT

It gets better, if i put a static ip from the same subnet it tells me another device has that IP. Something is really messed up. I have one device plugged into the firewall port.

Re: DHCPD issue with Firepower 7.0.1-7.1.0

babiojd01 — Fri, 15 Apr 2022 01:48:19 GMT

It ended up being something with NAT. Without the destination interface specified in the nat it cause a major DHCP malfunction.