Although the DNS resolver is the default DNS service in pfSense 2.2 and later, you can use DNS forwarder instead.

1. To do so, navigate to Services | DNS Forwarder and click on the Enable DNS forwarder checkbox (make sure to disable DNS resolver first). Many of the settings for DNS forwarder are identical to the DNS resolver settings. In this section, we will focus on the settings which are unique to DNS forwarder.
2. As with the DNS resolver, you can register DHCP leases and static mappings, but there is also an option called resolve DHCP mappings first.
3. Invoking this option causes the DHCP mappings to be resolved before the names provided in the Host Overrides and Domain Overrides tables.
4. The DNS Query Forwarding section has several unique options. The Query DNS servers sequentially checkbox, as the name implies, causes the DNS servers specified on the General Setup page to be queried sequentially instead of being queried at the same time.
5. The Require domain checkbox will drop DNS queries from upstream servers if they do not contain a domain (in other words, queries for plain names). The Do not forward private reverse lookups option, if enabled, results in the DNS forwarder not forwarding reverse lookups for RFC 1918 private addresses (10.0.0.0 addresses, 172.16.0.0 to 172.31.0.0 addresses, and 192.168.0.0 addresses).
6. The Strict interface binding checkbox causes the DNS forwarder to only bind to the IP addresses of interfaces selected in the Interfaces list box. If this option is not enabled, DNS forwarder will bind to all interfaces. Some of the settings available in the DNS resolver are also available in the DNS forwarder, such as the ability to set the port for resolving DNS queries, and the ability to bind only to selected interfaces.

One significant limitation of the DNS forwarder is that strict interface binding does not work with IPv6 addresses. As with the DNS resolver, the DNS forwarder allows you to add Host Overrides and Domain Overrides, and there is a field for Custom Options as well.