# Setting up an BGP Neighborship Connection

Last modified by Jean Franco on 2024/06/09 20:48
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In the example diagram above, an eBGP neighborship is set up between ER-L (AS 64512) and ER-R (AS 65000) which allows the neighbors to exchange routing information. In this case, ER-L will advertise the 198.51.100.x/26 networks to ER-R.

Follow the steps below to configure the BGP protocol on both routers:

CLI: Access the Command Line Interface on ER-L.You can do this using the CLI button in the GUI or by using a program such as PuTTY.

1. Enter configuration mode.

    configure

2. Define the BGP Autonomous System (AS) number and the Router ID.

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    set protocols bgp 64512 parameters router-id 203.0.113.1

3. Define the IP address and AS number used by the BGP neighbor.

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    set protocols bgp 64512 neighbor 192.0.2.1 remote-as 65000

4. As the neighbors are not directly connected, enable ebgp-multihop and additional options such as soft-reconfiguration.

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    set protocols bgp 64512 neighbor 192.0.2.1 ebgp-multihop 255
    set protocols bgp 64512 neighbor 192.0.2.1 soft-reconfiguration inbound

NOTE:The value set in the ebgp-multihop... command can be customized.

5. Create blackhole routes for the 198.51.100.x/26 networks that should be advertised into BGP.

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    set protocols static route 198.51.100.0/26 blackhole
    set protocols static route 198.51.100.64/26 blackhole
    set protocols static route 198.51.100.128/26 blackhole
    set protocols static route 198.51.100.192/26 blackhole

6. Advertise the 198.51.100.x/26 routes into BGP by using the network statement.

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    set protocols bgp 64512 network 198.51.100.0/26
    set protocols bgp 64512 network 198.51.100.64/26
    set protocols bgp 64512 network 198.51.100.128/26
    set protocols bgp 64512 network 198.51.100.192/26

NOTE:The network... statements in BGP must match the routes present in the routing table.

7. Commit the changes and save the configuration.

    commit ; save

CLI: Access the Command Line Interface on ER-R.You can do this using the CLI button in the GUI or by using a program such as PuTTY.

1. Enter configuration mode.

    configure

2. Define the BGP Autonomous System (AS) number and the Router ID.

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    set protocols bgp 65000 parameters router-id 192.0.2.1

3. Define the IP address and AS number used by the BGP neighbor.

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    set protocols bgp 65000 neighbor 203.0.113.1 remote-as 64512

4. As the neighbors are not directly connected, enable ebgp-multihop and additional options such as soft-reconfiguration.

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    set protocols bgp 65000 neighbor 203.0.113.1 ebgp-multihop 255
    set protocols bgp 65000 neighbor 203.0.113.1 soft-reconfiguration inbound

NOTE:The value set in the ebgp-multihop... command can be customized.

5. Commit the changes and save the configuration.

    commit ; save

The BGP neighborship and advertised/received routes can be verified with the following commands:

    show ip bgp summary
    show ip bgp
    show ip bgp neighbors 192.0.2.1 advertised-routes
    show ip bgp neighbors 192.0.2.1 received-routes

## Additional BGP Options

There are many other BGP options and additional features that can be configured when using BGP. Some of the more popular options are:

- Route-Maps
- Prefix-Lists
- BGP Communities
- Peer Groups
- Route Reflectors
- Confederations

See the output below for a list of available commands (output may differ between firmware versions):

    set protocols bgp 64512 ?
    Possible completions:
      address-family                    BGP address-family parameters
      aggregate-address                 BGP aggregate network
      dampening                         Enable route-flap dampening
      maximum-paths                     BGP multipaths
      neighbor                          BGP neighbor
      network                           BGP network
      parameters                        BGP parameters
      peer-group                        BGP peer-group
      redistribute                      Redistribute routes from other protocols into BGP
      timers                            BGP protocol timers

    set protocols bgp 64512 parameters ?
    Possible completions:
      always-compare-med                Always compare MEDs from different neighbors
      bestpath                          Default bestpath selection mechanism
      cluster-id                        Route-reflector cluster-id
      confederation                     AS confederation parameters
      dampening                         Enable route-flap dampening
      default                           BGP defaults
      deterministic-med                 Compare MEDs between different peers in the same AS
      distance                          Administratives distances for BGP routes
      enforce-first-as                  Require first AS in the path to match peer's AS
      graceful-restart                  Graceful restart capability parameters
      log-neighbor-changes              Log neighbor up/down changes and reset reason
      no-client-to-client-reflection    Disable client to client route reflection
      no-fast-external-failover         Disable immediate sesison reset if peer's connected link goes down
      router-id                         BGP router id
      scan-time                         BGP route scanner interval

    set protocols bgp 64512 neighbor 192.0.2.1 ?
    Possible completions:
      address-family                    Parameters relating to IPv4 or IPv6 routes
      advertisement-interval            Minimum interval for sending routing updates
      allowas-in                        Accept a route that contains the local-AS in the as-path
      attribute-unchanged               BGP attributes are sent unchanged
      capability                        Advertise capabilities to this neighbor
      default-originate                 Send default route to this neighbor
      description                       Description for this neighbor
      disable-capability-negotiation    Disable capability negotiation with this neighbor
      disable-send-community            Disable sending community attributes to this neighbor
      distribute-list                   Access-list to filter route updates to/from this neighbor
      ebgp-multihop                     Allow this EBGP neighbor to not be on a directly connected network
      fall-over                         Fall-over detection
      filter-list                       As-path-list to filter route updates to/from this neighbor
      local-as                          Local AS number
      maximum-prefix                    Maximum number of prefixes to accept from this neighbor
      nexthop-self                      Nexthop for routes sent to this neighbor to be the local router
      no-activate                       Disable the Address Family for this Neighbor
      override-capability               Ignore capability negotiation with specified neighbor
      passive                           Do not initiate a session with this neighbor
      password                          BGP MD5 password
      peer-group                        IPv4 peer group for this peer
      port                              Neighbor's BGP port
      prefix-list                       Prefix-list to filter route updates to/from this neighbor
      remote-as                         Neighbor BGP AS number [REQUIRED]
      remove-private-as                 Remove private AS numbers from AS path in outbound route updates
      route-map                         Route-map to filter route updates to/from this neighbor
      route-reflector-client            Neighbor as a route reflector client
      route-server-client               Neighbor is route server client
      shutdown                          Administratively shut down neighbor
      soft-reconfiguration              Soft reconfiguration for neighbor
      strict-capability-match           Enable strict capability negotiation
      timers                            Neighbor timers
      unsuppress-map                    Route-map to selectively unsuppress suppressed routes
      update-source                     Source IP of routing updates
      weight                            Default weight for routes from this neighbor

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Created by Jean Franco on 2024/06/09 20:48

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