Verify that the IPsec tunnels are functioning by attempting to ping the “inside tunnel addresses” of the VPC side of the tunnel by navigating to Firewall -> Virtual IP. There should be two virtual IP addresses configured that have Descriptions like “Inside address for tunnel to <remote IP address>”.
Amazon provides inside addresses for each end of the tunnel in a /30 subnet in IPv4 link local address space (169.254.x.y). Typically, the first usable address in the /30 is the inside address for the VPC end of the tunnel and the other usable address is the inside address for your end of the tunnel. So if you ping from one of the virtual IP addresses configured on the pfSense® Plus instance to the IP address that is one less (for example, if the virtual IP address were 169.254.253.22, ping from 169.254.253.22 to 169.254.253.21), that checks whether the other end of the tunnel is responding and whether the tunnel is functioning properly.
It sometimes takes a few minutes for the tunnels to begin working after the configuration wizard completes.
To ping, log into the pfSense® Plus instance via SSH and execute
a shell prompt. For the previous example of 169.254.253.22, the proper
ping -S 169.254.253.22 169.254.253.21
When pinging from a shell prompt, it is possible leave the command running indefinitely and interrupt it there is a response.
It is also possible to ping via the Diagnostics -> Ping page by selecting the appropriate source address and entering the remote tunnel inside address in the Host field. This will only send a limited number of ping packets, so it may be necessary to repeat this a few times.