When VPN tunnel connected, how is packet stream processed?

[DaleKnutsen]

Here is a beginner questions.

When a VPN tunnel is connected, where exactly does its packet stream enter the router's processing? i.e.:

Are packets from the tunnel processed by the firewall on the inbound interface, or does they effectively bypass the firewall?

Are packets from the tunnel subject to NAT, or do they bypass NAT?

[wong34539]

The packets are enter in to the exit tunnel interface of the router and then process the access list, NAT on which applied on that interface. After that it checks for the routing to route the packet.