Route everything through DialUp VPN with DHCP WAN address
I need to design with a Fortigate at HQ terminating DialUp IPsec VPNs from Fortigates at branch offices.
All user traffic from the branch offices should be routed through the VPN tunnel to HQ, and then to internet.
With a static IP on the WAN interface of the branch gates, this is easily accomplished by adding a static host-route (/32) to the HQ Peer IP thorugh the WAN gateway, and then add a default route (0.0.0.0/0.0.0.0) point to the DialUp VPN interface.
However, if the branch offices have DHCP assigned WAN interfaces - How can I accomplish this? As we don't know the gateway IP in advance we can't add the static host-route to the HQ gate and I don't want to rely on updating this static route manually if the DHCP gateway changes.
Hope you guys could give me a solution, many thanks!