bgp networks and subnet on the same router

Helo

I have network a.b.c.d/23 in my bgp configuration on my c28xx

On the same router on my LAN interface i'd like divide clas /23 on some subnets 4x a.b.c.d/25 etc and i have problem. When i configure subnets , my bgp stop advertise my prefix /23. When i delete subnets and i configure a.b.c.1/23 bgp works good.

There is possible to advertise in BGP prefix /23 and simultaneously have some subnets ?

thx for help

best regards

Pet

Reply to
pomidorek
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pomidorek pisze:

some outputs i conf

sh ip route C A.B.C.0/24 is directly connected, GigabitEthernet0/0 C A.B.C+1.0/24 is directly connected, Vlan2

sh ip bgp neighbors [ip] advertised-routes

Total number of prefixes 0

my conf router bgp [as] no synchronization bgp router-id [ip] bgp log-neighbor-changes network A.B.C.0 mask 255.255.254.0 neighbor [ip] remote-as [as] neighbor [ip] next-hop-self neighbor [ip] filter-list 4 in no auto-summary

Pet

Reply to
pomidorek

Pet,

Can you post your bgp configuration as well as your 'show ip bgp' output?

neteng

formatting link

Reply to
pcmccollum

sh ip route C 192.168.10.0/24 is directly connected, GigabitEthernet0/0 C 192.168.11.0/24 is directly connected, Vlan2

sh ip bgp neighbors [20.20.20.1] advertised-routes

Total number of prefixes 0

my conf router bgp [as] no synchronization bgp router-id [192.168.10.1] bgp log-neighbor-changes network 192.168.10.0 mask 255.255.254.0 neighbor [20.20.20.1] remote-as [as] neighbor [20.20.20.1] next-hop-self neighbor [20.20.20.1] filter-list 4 in no auto-summary

Pet

Pet,

ok I correct above Pet

Reply to
pomidorek

BGP network statement causes the local route to be advertised by BGP ONLY if the route is in the RIB (main routing table) when you split the subnet then the original route is no longer in the RIB

All you need to do is create a summary route in the RIB for the original /23 subnet:

ip route 192.168.10.0 mask 255.255.254.0 null0

router bgp network 192.168.10.0 mask 255.255.254.0

Reply to
Merv

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