I’ve create a lab with “classic BGP topology” → AS40002-AS40001-AS40003
Here ismy BGP config from AS40001 router:
[admin@MT-Test-AS1] > routing bgp peer print detail
Flags: X - disabled, E - established
0 E name=“AS-40002” instance=default remote-address=172.16.1.2 remote-as=40002 tcp-md5-key=“” nexthop-choice=default multihop=no route-reflect=no hold-time=3m ttl=default in-filter=“” out-filter=“”
address-families=ip default-originate=if-installed remove-private-as=no as-override=no passive=no use-bfd=no
1 E name=“AS-40003” instance=default remote-address=172.16.1.6 remote-as=40003 tcp-md5-key=“” nexthop-choice=default multihop=no route-reflect=no hold-time=3m ttl=default in-filter=“” out-filter=“”
address-families=ip default-originate=never remove-private-as=no as-override=no passive=no use-bfd=no
[admin@MT-Test-AS1] > routing bgp advertisements print
PEER PREFIX NEXTHOP AS-PATH ORIGIN LOCAL-PREF
AS-40002 77.240.240.0/24 172.16.1.1 40003 igp
AS-40002 77.240.248.0/24 172.16.1.1 40003 igp
AS-40002 75.140.140.0/24 172.16.1.1 igp
AS-40002 0.0.0.0/0 172.16.1.1 incomplete
AS-40002 78.140.140.0/24 172.16.1.1 igp
AS-40002 172.16.1.0/24 172.16.1.1 igp
AS-40003 193.138.191.0/24 172.16.1.5 40002 igp
AS-40003 193.138.188.0/24 172.16.1.5 40002 igp
AS-40003 75.140.140.0/24 172.16.1.5 igp
AS-40003 78.140.140.0/24 172.16.1.5 igp
AS-40003 172.16.1.0/24 172.16.1.5 igp
[admin@MT-Test-AS1] >
For some resone I can see routes that are belong to AS40003 on my AS40002 router.
Is it OK? Because I thing that AS40001 shouldn’t announce "by default» all AS’s that is connected to it.
Of cause I can filter this by filter list, but is it the right way?