Technical Tip: Prepending AS and filtering redistributed routes

[dbabic]

Description
This article describes how to advertise the redistributed routes.

Solution
The FortiGate can prepend the redistributed route through route map .

Apply the route map intended for the redistributed routes under them only as follow:

# config router bgp
set as 65001
set router-id 10.10.10.10
config neighbor
edit "10.20.20.75"
set remote-as 65002
next
end
config network
edit 1
set prefix 10.132.0.0 255.255.240.0
next
end
config redistribute "connected"
set status enable
set route-map "Route-Redistribute-RouteMAP"
end
config redistribute "rip"
end
config redistribute "ospf"
set status enable
set route-map "Route-Redistribute-RouteMAP"
end
config redistribute "static"
end
config redistribute "isis"
end
config redistribute6 "connected"
end
config redistribute6 "rip"
end
config redistribute6 "ospf"
end
config redistribute6 "static"
end
config redistribute6 "isis"
end
end

# config router route-map
edit "Route-Redistribute-RouteMAP"
config rule
edit 1
set match-ip-address " prefix-list-redistribute "
set set-aspath "65001 65001 65001"
next
end
next
end

# config router prefix-list
edit "prefix-list-redistribute"
config rule
edit 1
set prefix 10.139.0.0 255.255.240.0
unset ge
unset le
next
edit 2
set prefix 10.138.0.0 255.255.240.0
unset ge
unset le
next
end
next
end

The result should be as follow:

baxter-kvm04 # get router info bgp neighbors 10.20.20.75 advertised-routes
BGP table version is 1, local router ID is 10.10.10.10
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
*> 10.132.0.0/20    10.109.20.70                  100  32768        0 i
*> 10.138.0.0/20    10.109.20.70                       32768        0 65001 65001 65001 ?
*> 10.139.0.0/20    10.109.20.78             2         32768        0 65001 65001 65001 ?

Note: If the Route map is put under the neighbor configuration and under the redistribute route configuration the following output is expected

axter-kvm04 # get router info bgp neighbors 10.109.20.75 advertised-routes
BGP table version is 1, local router ID is 10.109.20.70
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
*> 10.138.0.0/20    10.109.20.70                       32768        0 65001 65001 65001 65001 65001 65001 ?
*> 10.139.0.0/20    10.109.20.78             2         32768        0 65001 65001 65001 65001 65001 65001 ?

Total number of prefixes 2