Cisco.Press.BGP.Commands

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uses the MD5 algorithm. Specifying this command causes the generation and checking of the MD5
digest on every segment sent on the TCP connection.
Configuring a password for a neighbor will cause an existing session to be torn down and a new one
established.
If you specify a BGP peer group by using the peer-group-name argument, all the members of the peer
group will inherit the characteristic configured with this command.
If a router has a password configured for a neighbor, but the neighbor router does not, a message such
as the following will appear on the console while the routers attempt to establish a BGP session between
them:
%TCP-6-BADAUTH: No MD5 digest from [peer s IP address]:11003 to [local router s
IP address]:179
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neighbor password
Similarly, if the two routers have different passwords configured, a message such as the following will
appear on the screen:
%TCP-6-BADAUTH: Invalid MD5 digest from [peer s IP address]:11004 to [local router s
IP address]:179
Examples The following example enables the authentication feature between this router and the BGP neighbor at
10.108.1.1. The password that must also be configured for the neighbor is bla4u00=2nkq.
router bgp 109
neighbor 10.108.1.1 password bla4u00=2nkq
Related Commands Command Description
neighbor peer-group (creating) Creates a BGP peer group.
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neighbor peer-group (assigning members)
neighbor peer-group (assigning members)
To configure a BGP neighbor to be a member of a peer group, use the neighbor peer-group command
in router configuration mode. To remove the neighbor from the peer group, use the no form of this
command.
neighbor ip-address peer-group peer-group-name
no neighbor ip-address peer-group peer-group-name
Syntax Description ip-address IP address of the BGP neighbor who belongs to the peer group
specified by the tag.
peer-group-name Name of the BGP peer group to which this neighbor belongs.
Defaults There are no BGP neighbors in a peer group.
Command Modes Router configuration
Command History Release Modification
11.0 This command was introduced.
Usage Guidelines The neighbor at the IP address indicated inherits all the configured options of the peer group.
Examples The following example assigns three neighbors to the peer group named internal:
router bgp 100
neighbor internal peer-group
neighbor internal remote-as 100
neighbor internal update-source loopback 0
neighbor internal route-map set-med out
neighbor internal filter-list 1 out
neighbor internal filter-list 2 in
neighbor 172.16.232.53 peer-group internal
neighbor 172.16.232.54 peer-group internal
neighbor 172.16.232.55 peer-group internal
neighbor 172.16.232.55 filter-list 3 in
Related Commands Command Description
neighbor peer-group (creating) Creates a BGP peer group.
neighbor shutdown Disables a neighbor or peer group.
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neighbor peer-group (creating)
neighbor peer-group (creating)
To create a BGP peer group, use the neighbor peer-group command in router configuration mode. To
remove the peer group and all of its members, use the no form of this command.
neighbor peer-group-name peer-group
no neighbor peer-group-name peer-group
Syntax Description peer-group-name Name of the BGP peer group.
Defaults There is no BGP peer group.
Command Modes Router configuration
Command History Release Modification
11.0 This command was introduced.
Usage Guidelines Often in a BGP speaker, there are many neighbors configured with the same update policies (that is,
same outbound route maps, distribute lists, filter lists, update source, and so on). Neighbors with the
same update policies can be grouped into peer groups to simplify configuration and make update
calculation more efficient.
Peer group members can spanned multiple logical IP subnets, and can transit, or pass along, routes from
one peer group member to another.
Once a peer group is created with the neighbor peer-group command, it can be configured with the
neighbor commands. By default, members of the peer group inherit all the configuration options of the
peer group. Members can also be configured to override the options that do not affect outbound updates.
Peer group members will always inherit the following configuration options: remote-as (if configured),
version, update-source, out-route-map, out-filter-list, out-dist-list, minimum-advertisement-interval,
and next-hop-self. All the peer group members will inherit changes made to the peer group.
If a peer group is not configured with a remote-as, the members can be configured with the
neighbor {ip-address | peer-group-name} remote-as command. This command allows you to create
peer groups containing EBGP neighbors.
Example for an IBGP Peer Group
In the following example, the peer group named internal configures the members of the peer group to
be IBGP neighbors. By definition, this is an IBGP peer group because the router bgp command and the
neighbor remote-as command indicate the same autonomous system (in this case, AS 100). All the
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neighbor peer-group (creating)
peer group members use loopback 0 as the update source and use set-med as the outbound route-map.
The neighbor internal filter-list 2 in command shows that, except for 172.16.232.55, all the neighbors
have filter-list 2 as the inbound filter list.
router bgp 100
neighbor internal peer-group
neighbor internal remote-as 100
neighbor internal update-source loopback 0
neighbor internal route-map set-med out
neighbor internal filter-list 1 out
neighbor internal filter-list 2 in
neighbor 172.16.232.53 peer-group internal
neighbor 172.16.232.54 peer-group internal
neighbor 172.16.232.55 peer-group internal
neighbor 172.16.232.55 filter-list 3 in
Example for an EBGP Peer Group
The following example defines the peer group named external-peers without the neighbor remote-as
command. This is what makes it an EBGP peer group. Each individual member of the peer group is
configured with its respective AS-number separately. Thus the peer group consists of members from
autonomous systems 200, 300, and 400. All the peer group members have set-metric route map as an [ Pobierz całość w formacie PDF ]

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