FortiGate
FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
aionescu
Staff
Staff
Description

This article describes how to configure the FortiGate to advertise, via BGP, static routes but filter the advertisement of the static default route.

Scope  
Solution aionescu_0-1645705798431.png

 

In this setup, there are two units involved the HUB and the SPOKE.

 

On the hub there are two static routes:

 

192.0.2.0/24 via the MPLS network

0.0.0.0/0 via port1 (INTERNET)

 

Between the hub and the spoke BGP is running.

 

BGP is already configured, and peering is UP.

 

Enabling redistribution of static routes on the HUB will, as expected, redistribute both static routes – 0.0.0.0/0 and 192.0.2.0/0:

 

HUB # show router static

config router static

    edit 1

        set gateway 10.191.31.254

        set device "port1"

    next

    edit 2

        set dst 192.0.2.0 255.255.255.0

        set gateway 172.16.100.2

        set device "MPLS"

    next

end

 

HUB # show router bgp

# config router bg

    set as 65000

    set router-id 172.16.102.1

    # config neighbor

        edit "172.16.102.2"

            set soft-reconfiguration enable

            set remote-as 65000

        next

    end

    # config redistribute "connected"

    end

    # config redistribute "rip"

    end

    # config redistribute "ospf"

    end

    # config redistribute "static"

        set status enable

 

SPOKE # get router info bgp neighbors 172.16.102.1 received-routes

VRF 0 BGP table version is 1, local router ID is 172.16.102.2

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal

Origin codes: i - IGP, e - EGP, ? - incomplete

 

   Network          Next Hop            Metric LocPrf Weight RouteTag Path

*>i0.0.0.0/0        10.191.31.254                 100      0        0 ? <-/->

*>i192.0.2.0        172.16.100.2                  100      0        0 ? <-/->

 

Total number of prefixes 2

 

In order to filter the default static route, a prefix list and a route-map are created to apply to the BGP neighbor configuration:

 

HUB # show router prefix-list

# config router prefix-lis

    edit "Filter-default"

        # config rul

            edit 1

                set action deny

                set prefix 0.0.0.0 0.0.0.0

                unset ge

                unset le

            next

            edit 2

                set prefix any

                unset ge

                unset le

            next

        end

    next

end

 

HUB # show router route-map

# config router route-ma

    edit "Filter-default"

        # config rul

            edit 1

                set match-ip-address "Filter-default"

                unset set-ip-nexthop

                unset set-ip6-nexthop

                unset set-ip6-nexthop-local

                unset set-originator-id

            next

        end

    next

end

 

HUB # show router bgp

# config router bg

    set as 65000

    set router-id 172.16.102.1

    # config neighbo

        edit "172.16.102.2"

            set soft-reconfiguration enable

            set remote-as 65000

            set route-map-out "Filter-default"

        next

 

For the new policy to take effect, the BGP session must be reset.

For this, soft reset option is used to to refresh the BGP routing table without disturbing existing BGP peering sessions.

 

HUB # execute router clear bgp ip 172.16.102.2 soft

 

It is possible to confirm that the default static route is no longer advertised.

 

HUB # get router info bgp neighbors 172.16.102.2 advertised-routes

VRF 0 BGP table version is 1, local router ID is 172.16.102.1

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal

Origin codes: i - IGP, e - EGP, ? - incomplete

 

   Network          Next Hop            Metric LocPrf Weight RouteTag Path

*>i192.0.2.0        172.16.100.2                  100  32768        0 ? <-/->

 

Total number of prefixes 1

 

Also on the spoke:

 

SPOKE # get router info bgp neighbors 172.16.102.1 received-routes

VRF 0 BGP table version is 1, local router ID is 172.16.102.2

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal

Origin codes: i - IGP, e - EGP, ? - incomplete

 

   Network          Next Hop            Metric LocPrf Weight RouteTag Path

*>i192.0.2.0        172.16.100.2                  100      0        0 ? <-/->

 

Total number of prefixes 1

 

Between the hub and the spoke BGP is running.

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