Using the above topology we will configure a single homed eBGP. Download lab here.
router bgp 101 no synchronization bgp log-neighbor-changes neighbor 22.214.171.124 remote-as 3 no auto-summary !
router bgp 3 no synchronization bgp log-neighbor-changes network 126.96.36.199 network 188.8.131.52 neighbor 184.108.40.206 remote-as 101 no auto-summary !
All that is left is to use OSPFv2 to distribute routes from FIREWALL to ENT1.
To verify just use the following “show” commands.
ISP1#show ip bgp neighbors BGP neighbor is 220.127.116.11, remote AS 3, external link BGP version 4, remote router ID 18.104.22.168 BGP state = Established, up for 00:00:42 Last read 00:00:42, last write 00:00:42, hold time is 180, keepalive interval is 60 seconds ... <rest of output deleted> ISP1#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 B 22.214.171.124/24 [20/2] via 126.96.36.199, 00:00:50 C 188.8.131.52/24 is directly connected, GigabitEthernet0/0 B 184.108.40.206/24 [20/2] via 220.127.116.11, 00:00:50
ISP1#show ip protocols Routing Protocol is "bgp 101" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set IGP synchronization is disabled Automatic route summarization is disabled Neighbor(s): Address FiltIn FiltOut DistIn DistOut Weight RouteMap 18.104.22.168 Maximum path: 1 Routing Information Sources: Gateway Distance Last Update 22.214.171.124 20 00:01:24 Distance: external 20 internal 200 local 200 ISP1#
Perform the same “show” commands on ENT1 to verify association.
Using a ping and traceroute command can check the Layer 3 connectivity for the entire path:
SERV1> ping 126.96.36.199 84 bytes from 188.8.131.52 icmp_seq=1 ttl=253 time=40.158 ms 84 bytes from 184.108.40.206 icmp_seq=2 ttl=253 time=21.494 ms 84 bytes from 220.127.116.11 icmp_seq=3 ttl=253 time=27.591 ms 84 bytes from 18.104.22.168 icmp_seq=4 ttl=253 time=22.309 ms 84 bytes from 22.214.171.124 icmp_seq=5 ttl=253 time=23.390 ms SERV1> trace 126.96.36.199 trace to 188.8.131.52, 8 hops max, press Ctrl+C to stop 1 184.108.40.206 2.539 ms 9.359 ms 9.216 ms 2 10.0.0.1 19.470 ms 20.039 ms 19.656 ms 3 *220.127.116.11 39.910 ms (ICMP type:3, code:3, Destination port unreachable) * SERV1>
Note the exam topics to not mention troubleshooting. Just configuring and verifying….