Initial bgp configuration, Adding bgp neighbors, Resetting bgp connections – Enterasys Networks Security Router X-PeditionTM User Manual

Page 163

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Overview

XSR User’s Guide 6-15

•

Permit a local BGP speaker to send the default route 0.0.0.0 to a neighbor as the default route:

neighbor default-originate

•

Configure the COMMUNITIES attribute to be sent to the neighbor at this IP address:

neighbor send-community

•

Permit interior BGP sessions to use any working interface for TCP links:

neighbor update-

source interface

•

Permit BGP sessions, even when the neighbor is not on a directly connected segment:

neighbor ebgp multihop

•

Specify the minimum interval between BGP routing update transmissions:

neighbor

advertisement-interval seconds

•

Configure MD5 authentication on a TCP link to a BGP peer:

neighbor password <value>.

For an example, refer to

“TCP MD5 Authentication for BGP Example”

on page 6-25.

•

Specify BGP routing updates to/from neighbors, as detailed in an ACL:

neighbor

distribute-list {ACL#}{in | out}

•

Set up a BGP filter:

neighbor filter-list ACL# {in | out}

•

Disable next-hop processing on BGP updates to a neighbor:

neighbor next-hop-self

•

Assign a route map to in or outbound routes:

neighbor route-map map-# {in | out}

•

Set the XSR to begin storing received updates:

neighbor soft-reconfiguration inbound

•

Disable a BGP neighbor or peer group:

neighbor shutdown

. Conversely, you can enable a

previously existing neighbor or neighbor peer group that was disabled with

no

neighbor

shutdown

For configuration examples, refer to

“Configuring BGP Peer Groups”

on page 6-25.

Initial BGP Configuration

Begin BGP configuration by enabling BGP routing:

•

Enable a BGP Routing process and acquire Router Configuration mode: router bgp <AS #>

•

Mark a “local” network in this AS, adding it as an entry in the BGP Routing table: network
<IP address> mask <subnet>

Adding BGP Neighbors

Adding neighbors to a BGP network is fundamental to building a BGP environment. You can add
internal neighbors (those inside an AS) or external neighbors (those in other AS’s). Usually,
external neighbors are next to each other and share a subnet while internal neighbors may be
situated anywhere in the same AS. The process on the XSR is as follows:

•

Add a BGP network: network <IP address> mask <mask>

•

Add a BGP neighbor: neighbor <IP address> remote-as <as #>

For an example, refer to

“Configuring BGP Neighbors”

on page 6-23.

Resetting BGP Connections

If you alter any BGP configuration values that you have defined for BGP neighbors, you must
reset that BGP connections for the configuration change to take effect.

•

Reset one or more BGP connections: clear ip bgp address

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