Using prefix-list to deny all traffic from Network blocks

Christopher Bell · ‎11-01-2007

Hello,

I'm a little confused about prefix lists. Everything I have read over the past few weeks regarding using prefix lists to deny traffic at the edge, suggests that I can use them rather than and ACL for simplicities sake.

For instance, if I were trying to deny the block 221.0.0.0/8 any traffic to our network, I would use:

ip prefix-list TEST deny abc.0.0.0/8 le 32

ip prefix-list TEST premit 0.0.0.0/0 le 32.

This didn't work however. I'm sure I'm missing something stupid. Prefix lists such as this don't have to be applied to a specific interface as an access list would does it?

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Collin Clark · ‎11-01-2007

Its applied to a routing process, typically BGP. Some people route the networks to null0 which can be easier for some to understand and troubleshoot.

HTH and please rate.