I'm a bit new to this, so let me give this a shot… Please let me know if there are more specific items I need to list.
I'm using 2.4.2-RELEASE-p1, DNS resolver with forwarding enabled to Google DNS ipv4 and ipv6 with interfaces set to its default of ALL.
Physical setup is a Qotom fanless box with i3 4025u + 4GB ram and quad intel i210 nics as follows: Cable modem > pfSense WAN >|> pfSense LAN+SPAN > Netgear GS108T managed switch (LAN) + Monitoring PC (SPAN) which is separate from my main PC.
Packages installed are Snort, pfBlockerNg, ntopng, nut, openvpn-client-export.
I tried powering off my main PC to see what how the traffic changes, and 127.0.0.1 now correctly resolves to the hostname of the device that performed the resolution; the target MAC address is still the same however. Originally 127.0.0.1 was resolving to gearssdk.opswat.com regardless of the device performing the resolution.