Embedded Ethernet - PIC18F452, Packet Whacker, CCS C

[splee]

I am doing an experiment with embedded Ethernet using the following:
- a PC (IP: 192.168.0.100, MAC: 00:1a:a0:02:92:98)
- an Embedded Ethernet (IP: 192.168.0.196, MAC: 30:30:30:30:39:36)with PIC18F452, Packet Whacker, RTL8019AS with CCS C as compiler)

At first, the PC sends a UDP "ECHO" request (dest. port 07, src. port 07) to the Packet Whacker. When the Whacker receives the packet, it swaps the source and destination IP & MAC address (as usual), but I changed the dest. MAC address a little bit to 00:1a:a0:02:92:00, and then send the packet. I would like to see if the PC still receive the "ECHO" reply packet even though the dest. MAC address has changed.

The fact is, the PC still receives the reply packet (see link below):
http://cid-93ca79cd8afe42d7.photos.live.com/self.aspx/New%20album/UDP.bmp

What actually happened? I thought packet with non-matching MAC address should be filtered by the RTL8019AS? Can somebody explain?