BGP neighbor next-hop-self

When peering is done via the external network of a BGP edge router within an AS, a BGP edge router will not change the next hop of for the route from the advertising AS when it receives it but rather will pass it on unchanged to its IBGP neighbors.

Setting the next-hop-self parameter on each of the edge router’s IBGP connections, ensures a reachable next hop without increasing the size of the IGP table. The next-hop-self command will allow us to force BGP, to use a specified IP address as the next hop rather than letting the protocol choose the nexthop.

Video Demonstration

from: Cisco IOS IP Routing: BGP Command Reference

neighbor next-hop-self

To configure the router as the next hop for a BGP-speaking neighbor or peer group, use the neighbor next-hop-self command in router configuration mode. To disable this feature, use the no form of this command.

neighbor {ip-address | peer-group-name} next-hop-self

no neighbor {ip-address | peer-group-name} next-hop-self

Syntax Description

ip-address	IP address of the BGP-speaking neighbor.
peer-group-name	Name of a BGP peer group.

Defaults

This command is disabled by default.

Command Modes

Router configuration

Command History

Release	Modification
10.0	This command was introduced.
11.0	The peer-group-name argument was added.
12.2(33)SRA	This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX	This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

Usage Guidelines

This command is useful in unmeshed networks (such as Frame Relay or X.25) where BGP neighbors may not have direct access to all other neighbors on the same IP subnet.

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. Specifying the command with an IP address will override the value inherited from the peer group.

For a finer granularity of control, see the set ip next-hop command.

Examples

The following example forces all updates destined for 10.108.1.1 to advertise this router as the next hop:

router bgp 109

 neighbor 10.108.1.1 next-hop-self

Related Commands

Command	Description
neighbor peer-group (creating)	Creates a BGP peer group.
set ip next-hop (BGP)	Indicates where to output packets that pass a match clause of a route map for policy routing.

Files:
Topology
Configs
BGP Configuration