Snort LAN alert source ip not local ip

[johnchon]

may i know why the source ip lan is another ip not range 192.168.0.x

[bmeeks]

Think about how network traffic works on a firewall. Once your LAN host initiates a conversation with another external host (through your LAN and then out of your WAN, for example), pfSense creates a state table entry that will now allow that external host to talk back to your internal LAN host. So if the external traffic starts a session it will be the "source" and your LAN host is the "destination". This would be the case if you clicked a web site URL. The web server will become the "source" of the web traffic and the browser and your LAN host the "destination" as the web server sends the HTTP or HTTPS traffic back to you.

So who is "source" and who is "destination" changes back and forth during operation.