Dell PowerConnect B-FCXs, Configuration Manual

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1040 PowerConnect B-Series FCX Configuration Guide
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Filtering
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The no-export keyword filters for routes with the well-known community “NO_EXPORT”. A route in
this community should not be advertised to any BGP4 neighbors outside the local AS. If the router
is a member of a confederation, the Layer 3 Switch advertises the route only within the
confederation. For information about confederations, refer to
“Configuration notes” on page 1021.
Defining a community ACL
To configure community ACL 1, enter a command such as the following.
PowerConnect(config)#ip community-list 1 permit 123:2
This command configures a community ACL that permits routes that contain community 123:2.
NOTE
Refer to “Matching based on community ACL” on page 1045 for information about how to use a
community list as a match condition in a route map.
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 1045.
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.