Isp on shared carrier (and it does strange things)

I’ve got an isp which offers a service on a shared carrier – the isp is kind of misconfigured in that it will try to route packets via the ip address of my peplink wan interface to some random destination network (a destination ip other than the ip of my peplink wan …). There is an idea that my peplink is then receiving the packet, seeing that it doesn’t have any internal routes to such a network and then reforwarding it back out one of its available wans as determined by outbound policy. Is this possible?

Can I stop this with an inbound firewall rule?


It seems most likely that this is actually not what was occurring. It appears more likely that the ISP had created a routing loop within their own equipment.

Is the WAN connection DHCP? If this is a static IP address, make sure the subnet mask is correct. A simple way to configure the firewall in your Peplink would be to set the default inbound firewall rule to “Deny” and only allow the desired incoming traffic with specific firewall rules.