TomatoUSB

I have an apparently working openvpn client (implemented with tomatovpn) connecting to a linux openvpn server machine. It has been working for a long time though from time to time I have observed something that I could not explain. It bothers me to no ends. Here's the deal: the connection is achieved via TUN interface with all necessary routing done on both server machine and clent router. Client vpn router is behind another modem-router combo and router is assigned with a LAN IP of 192.168.1.3. The Client vpn router has a local network of 192.168.5.0 and this network is known in the server machine so server could access its resources. Here's what I could not explain - from time to time right after vpn connection is established, I am seeing in log that certain incoming packets have bad source IP address

MULTI: bad source address from client [192.168.1.3], packet dropped

This really bothers me because the packets indicated are basically the VPN router itself referred to by the router-modem combo LAN ( the client VPN's WAN interface). How come packets of this addess would manage to penetrate into my VPN LAN and come through my TUN interface to my server???

Granted that I have activated gateway-redirect on my VPN network so client traffic will access server LAN to get to internet, but still traffic that exists beyond the client router really has no right to enter through my TUN interface. How do they get to my server???

Multihome device by any chance (e.g. a laptop connected both wired _and_ wirelessly, simultaneously, to two different networks)?

Rodney

as far as I can tell, the client vpn router only has one IP so it is not a multihome device. There is one way to go out to internet.