Am I being thick?

Dec 19, 2006 2 Replies

Guys



I'd appreciate a bit of help please



I have a large network, all cisco, all EIGRP, no reason or need to change



I have 2 core sites both running in a hub and spoke and both connected together



On all the spoke sites or satellite sites I want to stop traffic going to the other satellite and opposing core sites



I have a 20 bit network (FWIW)



One satellite site has an IP range 10.6.95.0/20



I want to stop all traffic getting to any


10.2.0.0 /20
10.3.0.0 /20
10.4.0.0 /20
10.5.0.0 /20

I created a set of access lists and applied them onto the S0/0 interface of the router, a basic deny anything to the above nets and it works



I want to move away from ACLs to route statements on some satellite centres, why?, cus I want to. Well it is my network



So on my 10.6.95.0 network I:



o Log onto a local server and start a ping to an IP address on a 10.2.0.0 network o Create a default route to route all traffic to S0/0 o Create a route for 10.2.0.0 255.255.0.0 null0 o Remove the EIGRP network o Watch the pings continue



Why does my traffic continue to get thru ?



In anticipation


--------- We don't stop playing because we get old We get old because we stop playing


This is one of the cornerstones of IP routing.

More specific routes are /always/ preferred over less specific ones.

10.2.0.0 255.255.0.0 null0

is less specific than

10.2.0.0 /20

If there are equally specific then the administrative distance is used to determine which one goes in the routing table.

The order then is:

- Prefix length - Within a routing protocol - cost - Between Routing protocols - admin dist.

I noticed just too late that I had not answered your question.

"Am I being thick?"

Yes:-)

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