Service Manual

NOTE: Dell Networking OS supports up to 255 characters in a set community statement inside a route
map.
NOTE: With Dell Networking OS, you can create inbound and outbound policies. Each of the commands
used for filtering has in and out parameters that you must apply. In Dell Networking OS, the order of
preference varies depending on whether the attributes are applied for inbound updates or outbound
updates.
For inbound and outbound updates the order of preference is:
• prefix lists (using the neighbor distribute-list command)
• AS-PATH ACLs (using the neighbor filter-list command)
• route maps (using the neighbor route-map command)
Prior to filtering BGP routes, create the prefix list, AS-PATH ACL, or route map.
For configuration information about prefix lists, AS-PATH ACLs, and route maps, refer to
Access Control Lists (ACLs).
NOTE
: When you configure a new set of BGP policies, to ensure that the changes are made, always reset
the neighbor or peer group by using the clear ip bgp command in EXEC Privilege mode.
To filter routes using prefix lists, use the following commands.
1 Create a prefix list and assign it a name.
CONFIGURATION mode
ip prefix-list prefix-name
2 Create multiple prefix list filters with a deny or permit action.
CONFIG-PREFIX LIST mode
seq sequence-number {deny | permit} {any | ip-prefix [ge | le] }
• ge: minimum prefix length to match.
• le: maximum prefix length to match.
For information about configuring prefix lists, refer to Access Control Lists (ACLs).
3 Return to CONFIGURATION mode.
CONFIG-PREFIX LIST mode
exit
4 Enter ROUTER BGP mode.
CONFIGURATION mode
router bgp as-number
5 Filter routes based on the criteria in the configured prefix list.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | peer-group-name} distribute-list prefix-list-name {in |
out}
Configure the following parameters:
• ip-address or peer-group-name: enter the neighbor’s IP address or the peer group’s name.
Border Gateway Protocol IPv4 (BGPv4) 254