You may find some weird messages indications in your syslog telling you something like “martian source” like the followings:

When a host needs send a package to another host, it can define the route on the network or use the default route. Those “source routed packages” are identified in Linux as martian packages. You can configure your Linux log/do not log those packages:

# echo 0 > /proc/sys/net/ipv4/conf/*/log_martians #do not log