I have been having problems configuring a VPN tunnel to a TP-Link ER605 router, the situation is that my client does not have a static public IP and is not willing to pay for one nor for a FortiGate device to simplify the work, I did the VPN tunnel configuration on my FortiGate 80F and I also configured the TP-Link router hoping that it could connect but I was not successful, which leads me to two questions:
Are these two brands somehow compatible in terms of VPN tunnel configuration?
If they are compatible, is it possible for it to work with Dial Up VPN mode or is it necessary for my client to have a static public IP for the connection to be possible?