Configuration Guide User guide

FastIron Configuration Guide 1401
53-1002494-02
Filtering
The deny | permit parameter specifies the action the software takes if a route community list
matches a match statement in this ACL. To configure the community-list match statements in a
route map, use the match community command. Refer to “Matching based on community ACL” on
page 1406.
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 routers at
all.
The <regular-expression> parameter specifies a regular expression for matching on community
names. For information about regular expression syntax, refer to “Using regular expressions to
filter” on page 1397. You can specify a regular expression only in an extended community ACL.
Defining IP prefix lists
An IP prefix list specifies a list of networks. When you apply an IP prefix list to a neighbor, the Layer
3 switch sends or receives only a route whose destination is in the IP prefix list. You can configure
up to 100 prefix lists. 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.
Brocade(config)#ip prefix-list Routesfor20 permit 20.20.0.0/24
Brocade(config)#router bgp
Brocade(config-bgp-router)#neighbor 10.10.10.1 prefix-list Routesfor20 out
These commands configure an IP prefix list named Routesfor20, which permits routes to network
20.20.0.0/24. The neighbor command configures the Layer 3 switch to use IP prefix list
Routesfor20 to determine which routes to send to neighbor 10.10.10.1. The Layer 3 switch sends
routes that go to 20.20.x.x to neighbor 10.10.10.1 because the IP prefix list explicitly permits these
routes to be sent to the neighbor.
Syntax: ip prefix-list <name> [seq <seq-value>] [description <string>] deny | permit
<network-addr>/<mask-bits> [ge <ge-value>] [le <le-value>]
The <name> parameter specifies the prefix list name. You use this name when applying the prefix
list to a neighbor.
The description <string> parameter is a text string describing the prefix list.
The seq <seq-value> parameter is optional and specifies the IP prefix list sequence number. You
can configure up to 100 prefix list entries. If you do not specify a sequence number, the software
numbers them in increments of 5, beginning with prefix list entry 5. The software interprets the
prefix list entries in numerical order, beginning with the lowest sequence number.