Task 1
| R1#show ip interface brief Interface IP-Address OK? Method Status Protocol FastEthernet0/0 10.1.0.1 YES manual up up Serial0/0 200.0.0.1 YES manual up up Serial0/1 10.0.0.5 YES NVRAM up up |
| R2#show ip interface brief Interface IP-Address OK? Method Status Protocol Ethernet0/0 200.0.0.5 YES manual up up Serial0/0 200.0.0.2 YES manual up up Loopback0 192.0.2.254 YES manual up up |
| R3#show ip interface brief Interface IP-Address OK? Method Status Protocol Ethernet0/0 10.3.3.1 YES manual up up Serial0/1 10.0.0.6 YES NVRAM up up Ethernet1/0 200.0.0.6 YES manual up up |
Task 2
| R1(config)#ip route 0.0.0.0 0.0.0.0 serial 0/0 |
| R1#ping 192.0.2.254Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.0.2.254, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms R1#ping 200.0.0.5 Type escape sequence to abort. |
Task 3
| R1(config)#router bgp 65001 R1(config-router)#bgp router-id 1.1.1.1 R1(config-router)#network 10.1.0.0 mask 255.255.0.0 R1(config-router)#neighbor 10.0.0.6 remote-as 65001 R3(config-router)#neighbor 10.0.0.5 timers 2 6 R1(config-router)#end |
| R3(config)#router bgp 65001 R3(config-router)#bgp router-id 3.3.3.3 R3(config-router)#neighbor 10.0.0.5 remote-as 65001 R3(config-router)#network 10.3.3.0 mask 255.255.255.128 R1(config-router)#neighbor 10.0.0.6 timers 2 6 R3(config-router)#end |
Following your configuration, use the show ip bgp summary and show ip bgp commands to verify your implementation. Following is the output of these commands on R3:
| R3#show ip bgp summary BGP router identifier 3.3.3.3, local AS number 65001 BGP table version is 4, main routing table version 4 2 network entries using 234 bytes of memory 2 path entries using 104 bytes of memory 3/2 BGP path/bestpath attribute entries using 372 bytes of memory 0 BGP route-map cache entries using 0 bytes of memory 0 BGP filter-list cache entries using 0 bytes of memory BGP using 710 total bytes of memory BGP activity 2/0 prefixes, 2/0 paths, scan interval 60 secsNeighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 10.0.0.5 4 65001 4 4 4 0 0 00:00:51 1 |
| R3#show ip bgp BGP table version is 4, local router ID is 3.3.3.3 Status codes: s suppressed, d damped, h history, * valid, > best, i – internal, r RIB-failure, S Stale Origin codes: i – IGP, e – EGP, ? – incompleteNetwork Next Hop Metric LocPrf Weight Path *>i10.1.0.0/16 10.0.0.5 0 100 0 i *> 10.3.3.0/25 0.0.0.0 0 32768 i |
To verify the configured BGP Hello and Hold timer values, you must use the show ip bgp neighbors command as follows:
| R3#show ip bgp neighbors 10.0.0.5 BGP neighbor is 10.0.0.5, remote AS 65001, internal link BGP version 4, remote router ID 1.1.1.1 BGP state = Established, up for 00:01:30 Last read 00:00:00, last write 00:00:00, hold time is 6, keepalive interval is 2 seconds Configured hold time is 6,keepalive interval is 2 seconds Minimum holdtime from neighbor is 0 seconds Neighbor capabilities: Route refresh: advertised and received(old & new) Address family IPv4 Unicast: advertised and received[Truncated Output] |
The final verification for this task is to perform a LAN-to-LAN ping between R1 and R3:
| R1#ping 10.3.3.1 source 10.1.0.1Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.3.3.1, timeout is 2 seconds: Packet sent with a source address of 10.1.0.1 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms |
| R3#ping 10.1.0.1 source 10.3.3.1Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.1.0.1, timeout is 2 seconds: Packet sent with a source address of 10.3.3.1 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/4 ms |
Task 4
This task calls for the configuration of Cisco IOS DHCP server and is completed as follows:
| R3(config)#ip dhcp excluded-address 10.3.3.1 10.3.3.5 R3(config)#ip dhcp pool LAN-POOL R3(dhcp-config)#network 10.3.3.0 /25 R3(dhcp-config)#default-router 10.3.3.1 R3(dhcp-config)#dns-server 10.1.0.253 10.1.0.254 R3(dhcp-config)#netbios-name-server 10.1.0.254 R3(dhcp-config)#domain-name howtonetwork.net R3(dhcp-config)#lease 8 R3(dhcp-config)#end |
Following this configuration, use the show ip dhcp pool command to verify the Cisco IOS DHCP server configuration settings. If you have actual hosts on the LAN, you can use the show ip dhcp binding command to see address allocations from the pool.
| R3#show ip dhcp pool LAN-POOLPool LAN-POOL : Utilization mark (high/low) : 100 / 0 Subnet size (first/next) : 0 / 0 Total addresses : 126 Leased addresses : 0 Pending event : none 1 subnet is currently in the pool : Current index IP address range Leased addresses 10.3.3.1 10.3.3.1 – 10.3.3.126 0 |
Alternatively, you can validate your configuration by looking at the router configuration:
| R3#show running-config | section dhcp ip dhcp excluded-address 10.3.3.1 10.3.3.5 ip dhcp pool LAN-POOL network 10.3.3.0 255.255.255.128 default-router 10.3.3.1 domain-name howtonetwork.net netbios-name-server 10.1.0.254 dns-server 10.1.0.253 10.1.0.254 lease 8 |
Task 5
This task requires a little thought but overall is a simple task. First, a default route pointing to R2 can be used to forward all Internet-bound traffic to this router. Because Ethernet is being used, specify a next hop IP address (and optionally interface). Specifying only an interface can result in intermittent connectivity. Additionally, since the 10.3.3.0/128 subnet is an RFC 1918 subnet, Network Address Translation (NAT) is required to allow the hosts on this subnet Internet access. This step is completed as follows:
| R3(config)#ip route 0.0.0.0 0.0.0.0 ethernet 1/0 200.0.0.5 R3(config)#ip access-list extended NAT-ACL R3(config-ext-nacl)#deny ip 10.3.3.0 0.0.0.127 10.1.0.0 0.0.255.255 R3(config-ext-nacl)#permit ip 10.3.3.0 0.0.0.127 any R3(config-ext-nacl)#exit R3(config)#interface ethernet 1/0 R3(config-if)#ip nat outside R3(config-if)#exit R3(config)#interface ethernet 0/0 R3(config-if)#ip nat inside R3(config-if)#exit R3(config)#ip nat inside source list NAT-ACL interface ethernet 1/0 overload R3(config)#exit |
Next, the backup link across the Internet should be enabled for OSPF; however, OSPF cannot be enabled on R2. Additionally, we are not allowed to configure any additional static routes. This requires a GRE tunnel between R1 and R3 (using R2 as transit) as follows:
| R1(config)#router ospf 1 R1(config-router)#router-id 1.1.1.1 R1(config-router)#exit R1(config)#interface fastethernet 0/0 R1(config-if)#ip ospf 1 area 0 R1(config-if)#exit R1(config)#interface tunnel 0 R1(config-if)#ip address 192.168.1.1 255.255.255.252 R1(config-if)#tunnel source serial 0/0 R1(config-if)#tunnel destination 200.0.0.6 R1(config-if)#ip ospf 1 area 0 R1(config-if)#end |
| R3(config)#router ospf 3 R3(config-router)#router-id 3.3.3.3 R3(config-router)#exit R3(config)#interface ethernet 0/0 R3(config-if)#ip ospf 3 area 0 R3(config-if)#exit R3(config)#interface tunnel 0 R3(config-if)#ip address 192.168.1.2 255.255.255.252 R3(config-if)#tunnel source ethernet 1/0 R3(config-if)#tunnel destination 200.0.0.1 R3(config-if)#ip ospf 3 area 0 R3(config-if)#exit |
Following this configuration, use the show interfaces command to verify the status of the tunnel then verify the OSPF adjacency using the show ip ospf neighbor command:
| R3#show interfaces tunnel 0 Tunnel0 is up, line protocol is up Hardware is Tunnel Internet address is 192.168.1.2/30 MTU 1514 bytes, BW 9 Kbit/sec, DLY 500000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation TUNNEL, loopback not set Keepalive not set Tunnel source 200.0.0.6 (Ethernet1/0), destination 200.0.0.1 Tunnel protocol/transport GRE/IP Key disabled, sequencing disabled Checksumming of packets disabled[Truncated Output] |
| R1#show interfaces tunnel 0 Tunnel0 is up, line protocol is up Hardware is Tunnel Internet address is 192.168.1.1/30 MTU 1514 bytes, BW 9 Kbit/sec, DLY 500000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation TUNNEL, loopback not set Keepalive not set Tunnel source 200.0.0.1 (Serial0/0), destination 200.0.0.6 Tunnel protocol/transport GRE/IP Key disabled, sequencing disabled Checksumming of packets disabled[Truncated Output] |
Continue and verify the OSPF adjacencies as follows:
| R1#show ip ospf neighborNeighbor ID Pri State Dead Time Address Interface 3.3.3.3 0 FULL/ – 00:00:35 192.168.1.2 Tunnel0 |
| R3#show ip ospf neighborNeighbor ID Pri State Dead Time Address Interface 1.1.1.1 0 FULL/ – 00:00:31 192.168.1.1 Tunnel0 |
Task 6
By default, following the configuration on R1 and R3, the OSPF routes will be preferred over the iBGP routes because of the lower administrative distance of OSPF as shown below:
| R3#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 routeGateway of last resort is 200.0.0.5 to network 0.0.0.0 200.0.0.0/30 is subnetted, 1 subnets |
| R1#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 routeGateway of last resort is 0.0.0.0 to network 0.0.0.0 1.0.0.0/32 is subnetted, 1 subnets |
In order to complete this task and ensure that the private link between R1 and R3 which is also running BGP is used as the preferred path, we need to adjust the default administrative distance of the better protocol (OSPF) allowing the iBGP routes, with a default administrative distance of 200, to be more preferred. This task is completed as follows:
| R1(config)#router ospf 1 R1(config-router)#distance ospf intra-area 201 inter-area 201 external 201 R1(config-router)#end |
| R3(config)#router ospf 3 R3(config-router)#distance ospf intra-area 201 inter-area 201 external 201 R3(config-router)#end |
The configuration can be validated using the show ip protocols command as follows:
| R3#show ip protocols | section ospf Routing Protocol is “ospf 3” Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Router ID 3.3.3.3 Number of areas in this router is 2. 2 normal 0 stub 0 nssa Maximum path: 4 Routing for Networks: Routing on Interfaces Configured Explicitly (Area 0): Tunnel0 Ethernet0/0 Reference bandwidth unit is 100 mbps Routing Information Sources: Gateway Distance Last Update 1.1.1.1 110 00:01:04 Distance: (default is 201) |
Following these configuration changes, the routing tables on R1 and R3 show the following:
| R3#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 routeGateway of last resort is 200.0.0.5 to network 0.0.0.0 200.0.0.0/30 is subnetted, 1 subnets |
| R1#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 routeGateway of last resort is 0.0.0.0 to network 0.0.0.0 1.0.0.0/32 is subnetted, 1 subnets |
Task 7
Perform the LAN-to-LAN ping between R3 and R1 as follows:
| R3#ping 10.1.0.1 source 10.3.3.1 repeat 100Type escape sequence to abort. Sending 100, 100-byte ICMP Echos to 10.1.0.1, timeout is 2 seconds: Packet sent with a source address of 10.3.3.1 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Success rate is 100 percent (100/100), round-trip min/avg/max = 1/3/4 ms |
Next, verify Internet access as follows:
| R3#ping 192.0.2.254 source 10.3.3.1 repeat 100Type escape sequence to abort. Sending 100, 100-byte ICMP Echos to 192.0.2.254, timeout is 2 seconds: Packet sent with a source address of 10.3.3.1 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Success rate is 100 percent (100/100), round-trip min/avg/max = 1/3/4 ms |
Following this ping, you can use the show ip nat translations command to verify NAT:
| R3#show ip nat translations Pro Inside global Inside local Outside local Outside global icmp 200.0.0.6:16 10.3.3.1:16 192.0.2.254:16 192.0.2.254:16 |
Task 8
Disable the Serial0/1 interface as follows:
| R3(config)#interface serial 0/1 R3(config-if)#shutdown R3(config-if)#end R3# *Mar 1 14:50:11.991: %SYS-5-CONFIG_I: Configured from console by console *Mar 1 14:50:12.959: %LINK-5-CHANGED: Interface Serial0/1, changed state to administratively down *Mar 1 14:50:13.959: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, changed state to down *Mar 1 14:50:15.963: %BGP-5-ADJCHANGE: neighbor 10.0.0.5 Down BGP Notification sent *Mar 1 14:50:15.963: %BGP-3-NOTIFICATION: sent to neighbor 10.0.0.5 4/0 (hold time expired) 0 bytes |
Next, verify the routing table using the show ip route command as follows:
| R3#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 routeGateway of last resort is 200.0.0.5 to network 0.0.0.0 200.0.0.0/30 is subnetted, 1 subnets |
Continuing with task validation, perform a LAN-to-LAN ping from R3 to R1 as follows:
| R3#ping 10.1.0.1 source 10.3.3.1 repeat 100Type escape sequence to abort. Sending 100, 100-byte ICMP Echos to 10.1.0.1, timeout is 2 seconds: Packet sent with a source address of 10.3.3.1 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Success rate is 100 percent (100/100), round-trip min/avg/max = 4/4/8 ms |
And finally, verify Internet access by pinging 192.0.2.254 from R3s LAN subnet as follows:
| R3#ping 192.0.2.254 source 10.3.3.1 repeat 100Type escape sequence to abort. Sending 100, 100-byte ICMP Echos to 192.0.2.254, timeout is 2 seconds: Packet sent with a source address of 10.3.3.1 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Success rate is 100 percent (100/100), round-trip min/avg/max = 1/3/4 ms |
Again, the show ip nat translations command can be used to verify NAT configuration:
| R3#show ip nat translations Pro Inside global Inside local Outside local Outside global icmp 200.0.0.6:22 10.3.3.1:22 192.0.2.254:22 192.0.2.254:22 |