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douglas1942
douglas1942
New Member
February 5, 2022
Solved

How to set BGP community attribute to BGP learned routes

  • February 5, 2022
  • 2 replies
  • 4268 views

Hello, I want to identify all BGP learned routes on a Fortigate and then apply a BGP Community attribute to them.

I am using an inbound route-map on the BGP peer for this purpose, however it does seem to work.

 

Is this the correct way to do this ?

 

config router route-map
edit "HG_CORP_ROUTE_MAP_IN"
config rule
edit 10
set match-origin egp***matching all learned incoming BGP routes
set set-community "7714:65100"***setting the community

Best answer by Toshi_Esumi

You still need to apply the route-map to each neighbor. Then if you want to set a specific community to all routes from the neighbor, I wouldn't bother matching anything but just apply the community. Then for other neighbors you might want to apply different communities. Otherwise, what's the purpose of applying a community?

They would be useful only when the FGT advertises those community-attached routes to other neighboring routing devices, or other VDOMs because communities are preserved when the routes are forwarded until removed/overwritten by a router on the path.

 

Or further, I would attach the community on the advertising router side when it advertises them to the FGT, which would be simpler.

 

Toshi

2 replies

Toshi_Esumi
SuperUser
Toshi_EsumiAnswer
SuperUser
February 6, 2022

You still need to apply the route-map to each neighbor. Then if you want to set a specific community to all routes from the neighbor, I wouldn't bother matching anything but just apply the community. Then for other neighbors you might want to apply different communities. Otherwise, what's the purpose of applying a community?

They would be useful only when the FGT advertises those community-attached routes to other neighboring routing devices, or other VDOMs because communities are preserved when the routes are forwarded until removed/overwritten by a router on the path.

 

Or further, I would attach the community on the advertising router side when it advertises them to the FGT, which would be simpler.

 

Toshi

akristof
Staff
akristof
Staff
February 6, 2022

Hello,

 

The route-map looks OK except the part that you are matching origin. That is not needed as you need to apply this route-map on neighbor on incoming direction. So all the routes will pass it automatically. But still, I would remove that origin criteria. Of course, after any change related to BGP, soft-clear the neighbor:

exec router clear bgp ip x.x.x.x soft

Then you can verify if the network received has community set:

get router info bgp network X.X.X.X/X

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