What does "Advised path" mean?

For the first time ever noticed this kernel message:

Apr 21 07:03:24 nx04 kernel: Advised path = IP of machine -> some other
IP, tos 00

Can someone explain in light words what this means? Is this a potential
threat?
Already tried to find an answer via Groups Google but found very few
references, one to a kernel patch containing that in connection with
LOG_MARTIANS and an ignored redirect. However, that line is missing from
my log. I grepped for that IP in all of our logs and found two rejects
logged a bit later in the firewall.log because it initiated connections
without a SYN packet.

Kai