Interface and Log Question

[TomT]

Hi.
My box has 4 x Intel LAN Ports.

Port 1 - WAN
Port 2 - LAN
Port 3 - Wireless AP
Port 4 - Not used.

In my System logs under Firewall, Normal View I see reference to the interface being used.

I get the occasional entry relating to em0 and it's always:
Default deny rule IPv4 (1000000103)   0.0.0.0   224.0.0.1 IGMP

I thought em0 is WAN ? I have other entries relating to WAN, but this entry always shows as em0 why and is it normal ?

Thanks

[TomT]

I should add my WAN is PPPOE, does that account for it ?