MX Firewall DHCP Custom Default Gateway

[Mosquitar]

Hi All,

I'm currently configuring an MX Firewall as a DHCP server and cant find an option to change the gateway IP address that DHCP allocates. This is required to support a migration as I want the MX to initially act as a DHCP server for the connected clients but for the clients to use the old firewall that is located on the same VLAN as their default gateway. Example below

Old Firewall (Gateway) - 192.168.1.1

New Meraki MX Firewall (DHCP Server) - 192.168.1.2 

Clients - 192.168.1.10 - 200

Can I override the DHCP gateway using custom option 3? 

[alemabrahao]

Maybe yes, check this link:

https://documentation.meraki.com/General_Administration/Cross-Platform_Content/Setting_Custom_DHCP_O...

Is it possible to perform a test?

[Mosquitar]

I cant test at the moment as I'm offsite. 

Looking at the link that you attached, it appears that the Meraki MX will automatically respond with 'Option 3 - Router' using it local IP address, however its not really clear if you can override Option 3 and specify a custom IP address.

It looks like this is possible in the dashboard, but I'm not sure if the MX will honour this or if it will override and return its own IP address

Has anyone tested this before?

[alemabrahao]

Give me a minute I will test it.

[alemabrahao · Accepted solution]

@Mosquitar I tested and It worked well. 🙂

[Mosquitar]

Thats great, I really appreciate you testing this. Much appreciated!!