Brocade Communications Systems Layer 3 Routing Configuration ICX 6650 - Manual (Page 351)

Brocade ICX 6650 Layer 3 Routing Configuration Guide 333
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Filtering
Filtering
This section describes the following:
• “Specific IP address filtering” on page 333
• “AS-path filtering” on page 334
• “BGP4 filtering communities” on page 338
• “Defining IP prefix lists” on page 340
• “Defining neighbor distribute lists” on page 341
• “Defining route maps” on page 342
• “Using a table map to set the tag value” on page 350
• “Configuring cooperative BGP4 route filtering” on page 351
Specific IP address filtering
You can configure the router to explicitly permit or deny specific IP addresses received in updates
from BGP4 neighbors by defining IP address filters. The router permits all IP addresses by default.
You can define up to 100 IP address filters for BGP4.
• If you want permit to remain the default behavior, define individual filters to deny specific IP
addresses.
• If you want to change the default behavior to deny, define individual filters to permit specific IP
addresses.
NOTE
Once you define a filter, the default action for addresses that do not match a filter is “deny”. To
change the default action to “permit”, configure the last filter as “permit any any”.
Address filters can be referred to by a BGP neighbor's distribute list number as well as by match
statements in a route map.
NOTE
If the filter is referred to by a route map match statement, the filter is applied in the order in which
the filter is listed in the match statement.
NOTE
You also can filter on IP addresses by using IP ACLs.
To define an IP address filter to deny routes to 10.157.0.0, enter the following command.
Brocade(config-bgp-router)#address-filter 1 deny 10.157.0.0 255.255.0.0
Syntax: address-filter num permit | deny ip-addr wildcard mask wildcard
The num parameter is the filter number.
The permit | deny parameter indicates the action the Layer 3 switch takes if the filter match is true.
• If you specify permit, the Layer 3 switch permits the route into the BGP4 table if the filter match
is true.
• If you specify deny, the Layer 3 switch denies the route from entering the BGP4 table if the filter
match is true.