firewall rules

hello,
I am using pfsense as my firewall. I set it up on an old computer, and it has two NIC's - one for lan and one for wan traffic. It is working fine, and I am using the "block all traffic" method of firewalls, then just poking holes in the firewall as needed.
That is also working fine, so my rules look like this

firewall
I was reading about the ideal firewall setup, and saw something that said a firewall should block any local traffic that doesn't originate from the lan. I take that to mean if a malicious computer tries spoofing you IP address or MAC address and tries to send traffic on your network, but even though the malicious computer has a valid MAC address, the traffic would still be coming from the wan, or outside of the lan.
So my question is, is there a way to test and confirm that your firewall will block this type of traffic. If there isn't a good way to test it, how about just confirming that the firewall would block this type of traffic?
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JeffBeallAsked:
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arnoldCommented:
Deals with a spoofed packet delivered to your firewall with the source address as being on your LAN.

The difficulty is you have LAN rules pictured.
In the WAN side is where the block would occur.
I.e, one old one dealt with injecting a PING packet destined to the broadcast addressed sourced ...


What programming tools are you familiar with?
Nmap is a network scanning tool.

One option if available on the wan to LAN side transition you could impose a block rule that will block any packet sourced on the LAN.
I.e. Internet excludes the 10.0.0.0/8 172.16.0.0/19 and 192.168.0.0/24 ip blocks.

There on the commercial rule the by default prevents an access from a LAN system to the wan IP:port that would forward back to an internal system.
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JeffBeallAuthor Commented:
thank you for the help
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