RFC 1911 IPs in my firewall logs

[Joe Brown]

Hello all,

Reviewing my home office firewall logs, I noticed an 
entry in which someone tried to connect to my 
external interface with an IP of 192.168.50.xx.  I 
assume it's a spoofed address, but I just don't know 
how they got it to traverse the Internet?  How can that 
be routed?

Thanks.