Here it is recommended to configure a DHCP server on the VLAN 103 port and set all phones to operate on VLAN 103. Then connecting LAN1 of the Wanderbox, and all IP phones, via the site’s LAN switch.. The IP phones will then operate on a VLAN with the subnet 192.168.103.0/24 using the same infrastructure as the main LAN on site.
This network diagram below depicted this scenario.
Figure 1: Using LAN1 as a DHCP client and VLAN 103 as a DHCP server