Thanks Steve, I'll do some more tests. I understand now I don't need DHCP but using it ensures portable clients will get the PfSense DNS resolver and not their default network settings. When they get on another network they will get their IP address and DNS as normal. I think this has been my problem - Knowing when DNS lookup is coming from PFsense or from the VPN private DNS servers direct. My Windows setup is using my preset fixed IPs and specified DNS servers which are Google or the ISP. Big mistake! I hadn't thought about DHCP with static lease mappings but I'll research. I don't know if that will allocate the IP address I want unless PfSense can use client MAC addresses. When I do a DNS leak test, all my external IPs show as the VPN provider along with their DNS addresses looking similar to their IP address. I don't see Google!
Without using the wrong network speak I'll explain what I and many others may want to achieve:
Small home networks using standard ISP supplied routers can be compromised by the addon 'Smart' clients that people are now just plugging in without considering DMZs or sub nets. Some U.K TV streaming (BBC & Netflix) and bank sites look for the public IP address and geolocation to allow access to their services. VPN providers using shared and rotated IP addresses are often blocked. In a family home network the ability to block websites or non-approved connected clients is important.
My pfsense setup at the moment is:
Local Lan for PCs using fixed IP addresses. A small block of IP addresses is assigned to 2 firewall Aliases - 'Pass to VPN' or 'Bypass VPN' to WAN public IP.
A DMZ interface with an IP address range for Smart TV, Media box and internet connected hard disc recorder. The DMZ accesses my Public IP. Any packets to or from the LAN are blocked. I regard the DMZ as low security.
A wifi interface connected to the LAN on a fixed IP using VPN.
This works for routing, blocking and allowing traffic, but I can't achieve DNS filtering. If I use DHCP fixed static mapping wouldn't there be uncertainty that another client could get the wrong IP? I may be dumb but it seemed to me that unless Pfsense could get a client MAC address it can't reliably use the rules set for it? I think that's why I concluded each client would need a fixed IP address and the pfsense DNS server address. On a small home network that's easy to configure for each client unless a wired laptop on a fixed IP moves elsewhere and won't connect wired to a DHCP router. WiFi connections aren't a problem because each connection on Windows defaults to DHCP. I'd like to use DHCP on PfSense, but I can't yet see how I can achieve selective routing?