How to find which machine using fake ip address

[malimail]

I got 106021 alert hundreds times every day, Pix automatic deny the revers path check, but this is happened on interface inside, I wonder if someone can show me a way to let me find which machine inside our LAN using the spoofed ip address to attack the pix.

Thanks

 

[routerman]

As you know the IP address of the machine, can you try nbtstat -A ip-addr

If its a windows pc this may help, gives you the logged on user and the machine name.