Multiple DHCP clients

I have a rather simple setup:

Ether1 connected to a cable modem, dhcp client and bridged to bridge1

Ether2 connected to bridge2, which is also a hotspot

Ether3 bridged to bridge1, its where I plug in my laptop to use the cable modem

All works fantastic (either that or I haven’t run into a problem yet!). EXCEPT if I use a cable modem that can serve multiple DHCP IP’s. What happens is the laptop in Ether3 will get served the second DHCP IP. In this case, the laptop is unable to surf. For sure DNS lookups won’t work. It appears to me like the firewall in the MT is not passing thru from the cable modem thru Ether1 to Ether3.

The laptop is set up as DHCP client. Can I get the MT to serve to Ether3 the same IP that Ether1 got? or, better yet, how can I get the second IP to work down the bridge1 to Ether3?

Thanks,

-Rich