DNS configuration on pfSense

[cogumel0]

I have pfSense as my router with 1 WAN and several LANs.

One of those LANs holds my DNS servers. I would like all clients across all LANs to use these DNS servers. What is the best way of achieving this bearing in mind pfSense acts as my DHCP server?

I can think of the following two:

1- Set DHCP to use pfSense as DNS server, set the pfSense DNS servers to my DNS servers and enable DNS forwarder

2- Set DHCP to use my DNS servers directly and open the firewall ports for incoming requests from all LANs to my DNS servers on port 53 UDP.

Which would be the best way of achieving this? Is there a better way other than the ones mentioned above?

EDIT: Suppose there is another option: set pfSense's DNS servers to my own and under System > General, disable DNS Forwarder and open up the firewall.

[Heli0s]

To reduce the complexity of your network setup, I would just add your current DNS servers to the DHCP options so that pfSense will hand out DHCP leases with those DNS servers. On the other hand, since your already have pfSense, why not remove those DNS servers and simply have pfSense act as the DNS server?