How can I discover a wifi smartnet camera connected to the LAN by DHCP

You can use command-line tool nmap to do a simple scan which will show you IP address and Mac address of devices (assuming you know or can find the mac address of the camera). So if your local network is on 192.168.1.x you would run this command to scan all addresses in the range 192.168.1.0 to 192.168.1.255

sudo nmap -sn 192.168.1.0/24

Or if you are on 192.168.0.x then:

sudo nmap -sn 192.168.0.0/24

Install nmap with

sudo apt install nmap