NULL 0

[sivakondalarao]

Wheh i put ip cache flow in my router , i saw that lot of traffic going towards the interface NULL 0 what it means

1) Is it the virus traffics

2)if not how this traffic is generated

[Richard Burts]

sivakondalarao

Without knowing more detail about how your router is configured it is difficult to give an exact answer to your question. But given what you have described I think it is not likely that this is virus traffic. I suspect that the traffic that shows up in the flow cache to null 0 is traffic which your router does not know how to forward (nost unreachable or network unreachable) and was discarded.

If you want to investigate this further I suggest that you take one or two examples from the flow cashe and do a show ip route for that destination address.

HTH

Rick

[jkell]

Null0 is used to mark packets/flows that should be discarded. This can be due to actual null routes, matching the "deny" in an ACL, or other issue. A CEF entry pointing to 'null0' is created to avoid reprocessing the route/ACL/etc for subsequent packets of a flow.