NAT (Network Address Translation) helps
to map many Private IP address into a single public address and send
the information to the internet. So your LAN IP address will be
hidden from the WAN. When there is traffic from your LAN to WAN, the
source IP addresses will be changed while NATing, and vise-versa
traffic the destination IP will be changed:

If you are exporting NetFlow packets
from the router using ‘IP route-cache flow’ or ‘IP flow ingress’ you
cannot view the WAN