To follow along with the examples in this chapter, you will need a pfSense system acting as a firewall with at least one node connected to it on the LAN side. To follow along with the DDNS examples, it will be helpful to have a DDNS domain. You can obtain free DDNS domains from such providers as No-IP and Duck DNS. If you want to try some of the more esoteric NTP options, you may want to obtain a GPS or PPS device and try to use those for synchronization. If you want to try configuring pfSense to act as an SNMP server, you’ll need at least one client device to confirm that it works.