By default Pritunl will add iptables rules to provide additional routing protection by restricting which networks a VPN client can access. The restrictions are added based on which networks are routed. This can create issues for some complex routing configurations. If you are having routing issues the restrictions can be disabled by unselecting Restrict Routing in the advanced server settings.
Many Pritunl configurations will require the instances to route traffic to different networks. By default this will be blocked by the source/dest check (AWS) or fowarding option (Google) and should be disabled (AWS) or enabled (Google) to avoid issues. This can be done on AWS in the Network Interfaces panel in the EC2 dashboard. For Google Cloud the forwarding option can be found in the network options when creating the instance.
Updated about 2 years ago