Licson Lee says to YSITD
Switch(config)# ip dhcp pool NAME Switch(dhcp-config)# network 192.168.90.0 255.255.255.0 Switch(dhcp-config)# default-router 192.168.90.1 Switch(dhcp-config)# dns-server 1.1.1.1 1.0.0.1 Switch(dhcp-config)# lease 1h