Allow gateway transit: Check this box if you have a virtual network gateway attached to this virtual network and want to allow traffic from the peered virtual network to flow through the gateway. The peered virtual network must have the Use remote gateways checkbox checked when setting up the peering from the other virtual network to this virtual network. Reference: https://docs.microsoft.com/en-us/azure/virtual-network/virtual-network-manage-peering#requirements-andconstraints