Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 441)

NOTE
Once you define a filter or ACL, the default action for communities that do not match a filter or ACL is
deny . To change the default action to permit , configure the last filter or ACL entry as permit any any .
Community filters or ACLs can be referred to by match clauses in a route map.
Defining a community ACL
To configure community ACL 1, enter a command such as the following. This command configures a
community ACL that permits routes that contain community 123:2.
device(config)# ip community-list 1 permit 123:2
Syntax: no ip community-list standard string [ seq seq-value ] deny | permit community-num
The string parameter specifies the ACL name. (If you enter a number, the CLI interprets the number as
a text string.)
The standard parameter specifies whether you are configuring a standard community ACL.
The seq seq-value parameter is optional and specifies the sequence number for the community list.
You can configure up to 199 entries in a community list. If you do not specify a sequence number, the
software numbers the entries in increments of 5, beginning with number 5. The software interprets the
entries in a community list in numerical order, beginning with the lowest sequence number.
The deny and permit parameters specify the action the software takes if a route community list
matches a match clause in this ACL. To configure the community-list match clauses in a route map, use
the match community command.
The community-num parameter specifies the community type or community number. This parameter
can have the following values:
• num:num - A specific community number
• internet - The Internet community
• no-export - The community of sub-autonomous systems within a confederation. Routes with this
community can be exported to other sub-autonomous systems within the same confederation but
cannot be exported outside the confederation to other autonomous systems or otherwise sent to
EBGP neighbors.
• local-as - The local sub-AS within the confederation. Routes with this community can be advertised
only within the local subAS.
• no-advertise - Routes with this community cannot be advertised to any other BGP4 devices at all.
The regular-expression parameter specifies a regular expression for matching on community names.
To use a community-list filter, use route maps with the match community parameter.
Defining and applying IP prefix lists
An IP prefix list specifies a list of networks. When you apply an IP prefix list to a neighbor, the device
sends or receives only a route whose destination is in the IP prefix list. The software interprets the prefix
lists in order, beginning with the lowest sequence number.
To configure an IP prefix list and apply it to a neighbor, enter commands such as the following.
device(config)# ip prefix-list Routesfor20 permit 10.20.0.0/24
device(config)# router bgp
device(config-bgp-router)# neighbor 10.10.10.1 prefix-list Routesfor20 out
Defining a community ACL
FastIron Ethernet Switch Layer 3 Routing Configuration Guide 441
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