Quick Reference Guide

PowerConnect B-Series TI24X Configuration Guide 795
53-1002269-02
Filtering
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Syntax: ip community-list standard <string> [seq <seq-value>] deny | permit <community-num>
Syntax: ip community-list extended <string> [seq <seq-value>] deny | permit
<community-num> | <regular-expression>
The <string> parameter specifies the ACL name. (If you enter a number, the CLI interprets the
number as a text string.)
The standard or extended parameter specifies whether you are configuring a standard community
ACL or an extended one. A standard community ACL does not support regular expressions whereas
an extended one does. This is the only difference between standard and extended IP community
lists.
The seq <seq-value> parameter is optional and specifies the community list sequence number. You
can configure up to 199 entries in a community list. If you do not specify a sequence number, the
software numbers them 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 | 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 800.
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-ASs within a confederation. Routes with this community can
be exported to other sub-ASs within the same confederation but cannot be exported outside
the confederation to other ASs 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” on
page 791. 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.
PowerConnect(config)# ip prefix-list Routesfor20 permit 20.20.0.0/24
PowerConnect(config)# router bgp
PowerConnect(config-bgp-router)# neighbor 10.10.10.1 prefix-list Routesfor20 out