topic Re: Possible to Use FTD as DHCP Server with multiple DNS servers in Network Security

Possible to Use FTD as DHCP Server with multiple DNS servers

mumbles202 — Thu, 13 Apr 2023 09:20:30 GMT

I'm in a situation where I need to use the FTD as the dhcp server for both my guest and internal subnet. At present I have it configured to give out my internal domain and dns servers. Can I use a FlexConfig configuration to modify the dns settings under the guest dhcp scope? I'd like to change this:

dhcpd address 172.27.200.100-172.27.200.199 Guest_Access dhcpd enable Guest_Access

to this

dhcpd address 172.27.200.100-172.27.200.199 Guest_Access dhcpd dns 4.2.2.2 8.8.8.8 interface Guest_Access dhcpd enable Guest_Access

This FTD is FMC managed running 7.2.0 code.

Re: Possible to Use FTD as DHCP Server with multiple DNS servers

MHM Cisco World — Thu, 13 Apr 2023 09:24:21 GMT

Solved: Specify DNS servers for DHCP server in FTD - Cisco Community

Re: Possible to Use FTD as DHCP Server with multiple DNS servers

balaji.bandi — Thu, 13 Apr 2023 11:11:03 GMT

Are you looking Guest and Internal have same subnet ?

or you looking 2 DHCP pool for Guest and Internal users ?

Re: Possible to Use FTD as DHCP Server with multiple DNS servers

mumbles202 — Thu, 13 Apr 2023 13:14:02 GMT

Ok thanks. Looks like it's not possible; back to drawing board now in terms of a solution for dhcp for that subnet.

Re: Possible to Use FTD as DHCP Server with multiple DNS servers

balaji.bandi — Thu, 13 Apr 2023 14:14:21 GMT

If i were you i will stick some small box run DHCP Server (using Linux in 10 - 20min time)

Re: Possible to Use FTD as DHCP Server with multiple DNS servers

mumbles202 — Sat, 15 Apr 2023 13:17:11 GMT

Guest and internal would need 2 different subnets with 2 different sets of dns servers since guest wouldn't be able to get dns from internal servers.

This is for an internal wireless solution so going to look to move the dhcp to the WLC.

Re: Possible to Use FTD as DHCP Server with multiple DNS servers

tomasz.gluszko — Fri, 11 Jul 2025 11:04:25 GMT

You have to do it through FlexConfig - it works.

Re: Possible to Use FTD as DHCP Server with multiple DNS servers

MHM Cisco World — Sun, 13 Jul 2025 12:21:44 GMT

Can you share flexconfig you use

MHM

Re: Possible to Use FTD as DHCP Server with multiple DNS servers

tomasz.gluszko — Sun, 13 Jul 2025 20:02:42 GMT

Flex "insert" once Type: Append

command just: dhcpd dns 4.2.2.2 8.8.8.8 interface Guest_Access