We just discovered a weird problem on our network. We have a /19 cut down in several .248 and .240
Now we connect to a provider, he puts in our routes in the BGP and assigns it to our port.
On our side we have a ip route 0.0.0.0 0.0.0.0 xxx.xxx.xxx.xxx that sends everything we dont have to the provider.
Now, the problem is the subnets of .248 and .240 which are NOT presently used seem to be creating a loop because of the following
if someone pings or has an old IP configured on his server which he is not supposed to have and for which the router has no route configuration this is what happens TTL EXPIRED IN TRANSIT. If we do a traceroute we see that the packet goes from the PROVIDER to US back to PROVIDER, back to US etc... etc...
How to prevent this? Do we need to assign the current unused subnets in a generic vlan as secondaries or something like that? so that it shows a REQUEST TIMED OUT instead or something??
What is the solution to this??