Technical Tip: How to advertise a static route configured with a Gateway IP in the BGP or ADVPN

[amrit]

Description	This article describes how to advertise a static route with a gateway IP in the BGP or ADVPN.
Scope	FortiOS 6. x.x, 7. x.x.
Solution	If an advertised static route in the BGP includes a gateway IP, the BGP next hop address will point to the gateway address of the static route by default. For example: HUBFGT-Kvm57(10.10.1.1)-------ADVPN/BGP-------(10.10.1.3)SpokeFGT-kvm51(Static route :10.220.230.0, Gateway IP:10.15.16.2) Spoke Firewall: Static route with a gateway IP: show router static config router static edit 1 set dst 10.220.230.0 255.255.255.0 set gateway 10.15.16.2 set device "port4" next end BGP summary on the spoke firewall: get router info bgp summary Neighbor V   AS     MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 10.10.1.1    4  65400 16181      16205      3          0     0      01w2d19h    1 get router info bgp neighbors 10.10.1.1 advertise Network                   Next Hop Metric LocPrf Weight RouteTag Path *>i10.220.230.0/24 10.15.16.2 100      32768     0         ?             <-/-> BGP routes on the hub: get router info bgp neighbors 10.10.1.3 received-routes Network                    Next Hop Metric LocPrf Weight RouteTag Path *>i10.220.230.0/24 10.15.16.2   100        0          0          ?        <-/-> This will cause communication failure to the network 10.220.230.0/24 from the Hub firewall because the Hub is unaware of the routing information for 10.15.16.2. The Hub will direct the traffic to subnet 10.220.230.0/24 using the default route. get router info routing-table details 10.15.16.2 Routing table for VRF=0 Routing entry for 0.0.0.0/0 Known via "static", distance 10, metric 0, best * 10.9.15.254, via port1 To solve this problem, enable the next-hop-self command in the BGP configuration of the spoke firewall: config neighbor show config neighbor edit "10.10.1.1" set next-hop-self enable set soft-reconfiguration enable set prefix-list-out "static" set remote-as 65400 next end get router info bgp neighbors 10.10.1.1 advertise Network                   Next Hop Metric LocPrf Weight RouteTag Path *>i10.220.230.0/24 10.10.1.3     100     32768   0           ?            <-/-> get router info bgp neighbors 10.10.1.3 received-routes Network                    Next Hop Metric LocPrf Weight RouteTag Path *>i10.220.230.0/24 10.10.1.3       100     0          0            ?            <-/-> get router info routing-table details 10.10.1.3 Routing table for VRF=0 Routing entry for 10.10.1.0/24 Known via "connected", distance 0, metric 0, best * is directly connected, HUB