12-03-2017 07:30 PM - edited 03-05-2019 09:35 AM
So when i apply an aggregate to an ebgp peer in as 10 for specific prefixes 172.16.2.1/24 and 172.16.3.1/24 I used the aggregate address of 172.16.0.0/22. So the ebgp peer that receives the aggregate sees 172.16.0.0/22 as expected but when i try to ping a specfic prefix such as the ones i mentioned above the router that is the ebgp peer of the as 10 router drops the packet. I even created a static route for the aggregate route on the ibgp router. As 500 is what the router that is ebgp peering with router in as 10 is in. And i have another router in as 500 ibgp peering with the router that is ebgp peering with the router in as 10.
Router in AS 10 <----->Router(EBGP)AS 500 and then iBGP router also in AS 500.
R5#show ip route<---Router in AS 10
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
4.0.0.0/32 is subnetted, 1 subnets
S 4.4.4.4 [1/0] via 55.55.55.2
55.0.0.0/30 is subnetted, 1 subnets
C 55.55.55.0 is directly connected, Serial2/3
5.0.0.0/32 is subnetted, 1 subnets
C 5.5.5.5 is directly connected, Loopback0
172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
B 172.16.0.0/22 [200/0] via 0.0.0.0, 00:51:10, Null0
C 172.16.2.0/24 is directly connected, Loopback1
C 172.16.3.0/24 is directly connected, Loopback2
R5#show ip bgp
BGP table version is 19, local router ID is 172.16.3.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 4.4.4.4/32 55.55.55.2 0 32768 ?
*> 172.16.0.0/22 0.0.0.0 32768 i
s> 172.16.2.0/24 0.0.0.0 0 32768 i
s> 172.16.3.0/24 0.0.0.0 0 32768 i
Router in AS 500 that is an eBGP with R5 in AS 10---->R4#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/193] via 10.1.1.1, 03:54:50, Serial2/0
4.0.0.0/32 is subnetted, 1 subnets
C 4.4.4.4 is directly connected, Loopback0
55.0.0.0/30 is subnetted, 1 subnets
C 55.55.55.0 is directly connected, Serial2/3
5.0.0.0/32 is subnetted, 1 subnets
S 5.5.5.5 [1/0] via 55.55.55.1
172.16.0.0/22 is subnetted, 1 subnets
B 172.16.0.0 [20/0] via 5.5.5.5, 00:52:58
10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
O 10.3.1.0/30 [110/192] via 10.1.1.1, 02:35:27, Serial2/0
O 10.2.1.0/30 [110/128] via 10.1.1.1, 03:54:50, Serial2/0
C 10.1.1.0/30 is directly connected, Serial2/0
C 10.50.1.1/32 is directly connected, Loopback5
12-04-2017 01:48 PM
R1#show ip bgp
BGP table version is 2, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 1.1.1.1/32 0.0.0.0 0 32768 i
* i4.4.4.4/32 5.5.5.5 0 100 0 20 ?
* i172.16.0.0/22 5.5.5.5 0 100 0 20 i
After doing what you instructed this is my BGP table on R1
12-04-2017 01:36 PM
In addition to previous post you also seem to be peering between R4 and R1 on multiple IPs.
Just use the loopback IPs to peer with.
Jon
12-04-2017 01:26 PM
Not sure what you have done because now R4 is seeing the summary via R1.
As Julio says can you provide at least the BGP configurations from all routers.
Jon
12-04-2017 01:31 PM
I think I accidently did next-hop-self on R1 to R4.
12-04-2017 01:38 PM
I removed all the next-hop-self commands. Starting over regarding those commands.
12-04-2017 01:45 PM
You use it on the routers receiving EBGP routes and then advertising them to IBGP peers.
So in your example you use it on R4 and configure it with the R1 neighbor.
Note also you should not be adding static routes for the summary address anywhere other than the router you are originally advertising it from and even there you may not need it (see earlier post).
Jon
12-04-2017 01:50 PM
So on R4 I configured for next-hop-self towards R1 "neighbor 1.1.1.1 next-hop-self"
12-04-2017 01:56 PM
Yes, assuming you are using the loopbacks for peering.
Jon
12-04-2017 02:07 PM
Should I peer again with 5.5.5.5 after deleting that peership? I can't even successfully ping 55.55.55.0 addresses from R1
12-04-2017 01:56 PM
R1#traceroute 172.16.2.1
Type escape sequence to abort.
Tracing the route to 172.16.2.1
1 10.1.1.2 20 msec 24 msec 20 msec
2 * *
R1#traceroute 172.16.2.1 sou
R1#traceroute 172.16.2.1 source 1.1.1.1
Type escape sequence to abort.
Tracing the route to 172.16.2.1
1 10.1.1.2 32 msec 24 msec 20 msec
2 55.55.55.1 40 msec 40 msec 40 msec
Interesting...
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide