En la Documentación Oficial tienes informacion respecto a ese y muchos temas mas.
https://doc.pfsense.org/index.php/Main_Page
Host = 1 IP / FQDN = 1 PC/Server/Dispositivo (ejemplo: 192.168.1.15)
Enter as many hosts as you would like. Hosts must be specified by their IP address or fully qualified domain name (FQDN). FQDN hostnames are periodically re-resolved and updated. If multiple IPs are returned by a DNS query, all are used.
Network = Varias IP = Segmento de Red (ejemplo: 192.168.1.0/24)
Networks are specified in CIDR format. Select the CIDR mask that pertains to each entry. /32 specifies a single IPv4 host, /128 specifies a single IPv6 host, /24 specifies 255.255.255.0, /64 specifies a normal IPv6 network, etc. Hostnames (FQDNs) may also be specified, using a /32 mask for IPv4 or /128 for IPv6. You may also enter an IP range such as 192.168.1.1-192.168.1.254 and a list of CIDR networks will be derived to fill the range.