In the previous two chapters, we covered the services and features of pfSense that are essential in most network scenarios. It is difficult to imagine a network of any size not implementing a DHCP server, and captive portals are extremely useful in setting up a public Wi-Fi network. The services that have been omitted until this chapter are those that you may not have occasion to implement on your network, yet they are all vital in their own way.

In this chapter, we will cover the Domain Name System (DNS) and discuss the two different ways to implement it in pfSense. We will also provide a preview of Chapter 6, Firewall and NAT, and demonstrate how to use firewall rules to prevent users from bypassing your DNS settings. We will also cover Dynamic DNS (DDNS), why it is useful, and how to implement it. Finally, we will cover two services that are not configured as often, but are still significant: Network Time Protocol (NTP) and Simple Network Management Protocol (SNMP).

This chapter should provide you with an understanding of the following topics:

• Introduction to DNS 
• Configuring DNS 
• Configuring DDNS 
• Network Time Protocol (NTP) 
• Simple Network Management Protocol (SNMP)