topic Re: Shun Interface in Network Security

Shun Interface

rmeans — Mon, 11 Mar 2019 13:37:22 GMT

When shunning, how is the interface decided?

show shun

shun (outside) 1.1.1.1 0.0.0.0 0 0 0

shun (inside) 2.2.2.2 0.0.0.0 0 0 0

I believe both IP addresses should be shunned on the outside interface.

Re: Shun Interface

Syed Iftekhar Ahmed — Thu, 28 Aug 2008 20:51:36 GMT

As per my understanding

The decision order is as follows

1. Static NAT entry

All static entries are checked to see if there is an entry with the global IP as the shunned IP. If there is then the actual shunned IP would be the local IP and the interface would be the local interface.

2. check the global addresses in the xlate and same process as above

3. If there is still no match, then a route lookup to figure out the source interface for this address and apply the shun to the interface returned by the route lookup.

Syed Iftekhar Ahmed

Re: Shun Interface

rmeans — Fri, 29 Aug 2008 11:32:39 GMT

Thanks. I found a static entry that should have been a class C but instead referenced a class B.