Prefix Rules

Overview:

Filtering is used for both input and output of the routing information. Once a filter is defined, it can be applied in any direction.

Functionality:

Route Filters can be divided into 2 categories

1) Access Lists
2) Prefix Lists

Prefix List entries determine parts of networks which can be allowed or denied. A prefix is a portion of an IP Address, starting from the far left bit of the far left octet. By specifying exactly how many bits of an address belong to a prefix, you can then use prefixes to aggregate addresses and perform some function on them, such as redistribution (filter routing updates). Prefix lists are used for route filters.

Detailed information on each parameter is beyond the scope of the document as is part of understanding Filtering. Information on different configuration parameters can be found http://docs.frrouting.org/en/stable-7.3/filter.html

Configuration Parameters

Add a Prefix List

Use Cases:

Access and Prefix Lists are mainly used in context with BGP and OSPF.