If you want to see what DHCP leases have been issued, navigate to Status | DHCP Leases. This page offers several pieces of information about active and inactive leases:

• The IP address of the lease.
• The MAC address of the client that has received the lease.
• The hostname of the client.
• A description of the client, if one is available.
• The start and end time of the lease.
• Whether the client is online, and the type of lease: static, active, inactive. Static is for statically mapped DHCP leases; active and inactive is for dynamically allocated leases. Active denotes those clients that are using their leases, while inactive is for inactive clients whose DHCP leases have  not yet expired.

To find out what DHCPv6 leases have been issued, navigate to Status | DHCPv6 Leases. All of the information about DHCP leases that the DHCP Leases page contains is contained on the DHCPv6 Leases page with respect to DHCPv6 leases. The leases table also has two additional fields. IAID is each lease's Identity Association ID. An Identity Association (IA) is a collection of addresses assigned to a client, and each IA has its own ID – the IAID. DUID is the DHCP Unique Identifier, which is a globally unique identifier each DHCPv6 client and server has for identification purposes.

There is a second table on this page called delegated prefixes. The purpose of this table is to list all prefixes that have been assigned to clients, so they can act as routers. Once again, the IAID and DUID are present in the table, as well as the start and end time of the delegation, and the state of the delegation. Note that a client must request a delegation from pfSense before it appears in this table.