The IP Office virtual machine deploys with two network interfaces. By default these configure as eth0 (192.168.42.1/255.255.255.0) and eth1 (192.168.43.1/255.255.255.0) when the virtual machine starts. The IP Office uses these as LAN1 and LAN2 respectively.

If eth1 (LAN2) is not required, you can disable the port. Doing that reduces the chances of IP address duplication, which causes the IP Office application to not start. See Duplicate IP address issue.