P. Gupta's questions

I have an ubuntu 18.04 router with several LAN interfaces:

1st interface: 2 port 10G NIC (the interfaces are bonded/teamed) bond1: interfaces: [enp5s0f0, enp5s0f1]

2nd interface: 4 port NIC enp8s0f0, enp8s0f1, enp9s0f0, enp9s0f1

The router functions as a gateway and DHCP server. Currently the 1st and 2nd interfaces are bridged together to 192.168.0.1 (the LAN interface). My current netplan configuration is the following:

 # This file describes the network interfaces available on your system
 # For more information, see netplan(5).
 network:
   version: 2
   renderer: networkd
   ethernets:
     enp0s8:
       dhcp4: no
       dhcp6: no
       addresses: [69.59.34.150/24]
       gateway4: 69.59.34.1
       nameservers:
       addresses: [69.60.173.84, 8.8.8.8]
       optional: true
     enp0s9:
       dhcp4: no
       dhcp6: no
     enp2s0f0:
  dhcp4: no
  dhcp6: no
     enp2s0f1:
       dhcp4: no
       dhcp6: no
     enp5s0f0:
       dhcp4: no
       dhcp6: no
     enp5s0f1:
       dhcp4: no
       dhcp6: no
     enp8s0f0:
       dhcp4: no
       dhcp6: no
     enp8s0f1:
       dhcp4: no
       dhcp6: no
     enp9s0f0:
       dhcp4: no
       dhcp6: no
     enp9s0f1:
       dhcp4: no
       dhcp6: no
   bonds:
     bond0:
       interfaces: [enp2s0f0, enp2s0f1]
       parameters:
             mode: 802.3ad
             lacp-rate: fast
             mii-monitor-interval: 100
     bond1:
       interfaces: [enp5s0f0, enp5s0f1]
       parameters:
             mode: 802.3ad
             lacp-rate: fast
             mii-monitor-interval: 100
   bridges:
     br0:
       addresses: [192.168.0.1/24]
       gateway4: 192.168.0.254
       routes:
       - to: 10.10.10.0/24
         via: 192.168.0.254
       - to: 20.20.20.0/24
         via: 192.168.0.254
       interfaces: [enp8s0f0, enp8s0f1, enp9s0f0, enp9s0f1, bond1]
       parameters:
            stp: false
            forward-delay: 0

Note that there are several other interfaces, but my question relates to br0 which bridges the 4 port NIC and the 2 port 10G NIC - they are all on the same subnet 192.168.0.x. I have specified a gateway (a switch at 192.168.0.254) for static routing of VLANs.

I would like to break up the 4 port NIC and the 2 port 10G NIC into different subnets (i.e 2 different bridges). The new schema:

2 port 10G NIC on subnet 192.168.0.x 4 port NIC on subnet 192.168.1.x

I would need to retain the DHCP functionality as well on both subnets (supplied by the same box).

My dhcpd.conf is as follows:

 subnet 192.168.0.0 netmask 255.255.255.0 {
    range 192.168.0.10 192.168.0.240;
         option routers 192.168.0.1;
    option domain-name "xxxxxx.org yyyyyyy.com";
    option domain-name-servers 192.168.0.1;
    option broadcast-address 192.168.0.255;
 }


 host DELL_PowerConnect_6248P {
         hardware ethernet aa:bb:cc:dd:ee:ff;
         fixed-address 192.168.0.254;
         option host-name "DELL_Powerconnect_6248P";
 }

My question is specifically this: Can I separate the two NICs by creating another bridge with just the 4 port NIC on subnet 192.168.1.x and then just add another subnet in the DHCP configuration file and have everything work?

My reasoning for doing this is simple. The 10G NIC is connected to a Layer 3 switch (dedicated), and I would like to use the other 4 ports to function just like a home router. In theory this seems like it would work, but my concern is retaining the DHCP functionality across both subnets. Thank you in advance for any assistance you can provide.