On 2017-03-01, Mike Hammett <[email protected]> wrote: > nexthop qualify via ( bgp | default ) If set to bgp , bgpd(8) may use > BGP routes to verify nexthops. If set to default , bgpd may use the > default route to verify nexthops. By default bgpd will only use static > routes or routes added by other routing daemons like ospfd(8) . > > What is it that this does?
This is for step 2 in the route decision process shown in bgpd(8)'s DESCRIPTION section. The nexthop is normally only considered reachable if it's either on a directly connected interface, or where an OSPF or static route points at the nexthop. Having the nexthop for one BGP route reached by the default route or by another BGP route is legal, but would be an unusual and often unwanted configuration.
