Technical Tip: Blackhole route for BGP Summarization

[Serxhio]

Description	This article describes a BGP route summarization technique.
Scope	FortiGate.
Solution	This article considers the following connected networks: 10.174.0.0/20. 10.163.0.0/20. The purpose is to advertise networks via a summary route. BGP will not advertise networks that are not in the RIB. To advertise the networks by a single summary route, a matching blackhole route can be added to the routing table. config router static     edit 2         set dst 10.160.0.0 255.240.0.0         set distance 254         set blackhole enable     next  end The entry for 10.160.0.0/20 is now in the RIB. Create a prefix list: config router prefix-list     edit "blackhole_summary"         config rule             edit 1                 set prefix 10.160.0.0 255.240.0.0                 unset ge                 unset le             next         end     next end Put the prefix list in a route map: config router route-map     edit "B_S"         config rule             edit 1                 set match-ip-address "blackhole_summary"             next         end     next end Redistribute the static routes on BGP by filtering on the route map created: config router bgp     config redistribute "static"         set status enable         set route-map "B_S"     end end Result: