Nexthopself

Nexthopself, often written as next-hop-self, is a BGP feature that forces the next-hop attribute of routes advertised to a BGP peer to be the advertising router’s own address. It is commonly used in iBGP deployments and is supported by most major network equipment vendors. The technique helps ensure that internal routes redistributed within an AS have a reachable next-hop for other iBGP peers, especially in hub-and-spoke topologies or when route reflectors are not used.

In standard BGP behavior, routes learned from one iBGP neighbor are advertised to other iBGP peers with their original next-hop preserved. This can leave the next-hop unresolved for some peers if the original next-hop is outside the local IGP or not reachable across the iBGP mesh. By applying nexthopself to advertisements to a particular peer, the router replaces the next-hop with its own address (the interface used to reach that peer). The result is a reachable, internal next-hop for all iBGP neighbors in the same domain.

Common use cases include simplifying iBGP full-mesh requirements, enabling clear reachability in route-reflector or non-reflector designs, and ensuring consistent next-hop behavior when connecting multiple internal routing domains. It is often part of deliberate topology design to avoid relying on external or remote next-hops inside an autonomous system.

Configuration is vendor-specific but follows the same principle: enable the next-hop-self behavior on the BGP session or group with the peer. For example, Cisco IOS commonly uses the command neighbor <peer> next-hop-self, while Juniper devices use set protocols bgp group <name> neighbor <peer> next-hop-self. Operators should ensure the chosen next-hop is reachable via the IGP or static routes to prevent routing issues.