1.5.10 Packet Tracer - Verify Directly Connected Networks (Instructor Version)
Addressing Table
| Device | Interface | IP Address / Prefix | Default Gateway |
|---|---|---|---|
| R1 | G0/0/0 | 172.16.20.1/25 | N/A |
| G0/0/1 | 172.16.20.129/25 | N/A | |
| S0/1/0 | 209.165.200.225/30 | N/A | |
| PC1 | NIC | 172.16.20.10/25 | 172.16.20.1 |
| PC2 | NIC | 172.16.20.138/25 | 172.16.20.129 |
| R2 | G0/0/0 | 2001:db8:c0de:12::1/64 | N/A |
| G0/0/1 | 2001:db8:c0de:13::1/64 | N/A | |
| S0/1/1 | 2001:db8:c0de:11::1/64 | N/A | |
| fe80::2 | N/A | ||
| PC3 | NIC | 2001:db8:c0de:12::a/64 | fe80::2 |
| PC4 | NIC | 2001:db8:c0de:13::a/64 | fe80::2 |
Objectives
- Verify IPv4 Directly Connected Networks
- Verify IPv6 Directly Connected Networks
- Troubleshoot connectivity issues.
Background
Routers R1 and R2 each have two LANs. Your task is to verify the addressing on each device and verify connectivity between the LANs.
Note: The user EXEC password is cisco. The privileged EXEC password is class.
Instructions
Part 1: Verify IPv4 Directly Connected Networks
Step 1: Verify IPv4 addresses and port status on R1.
a. Check the status of the configured interfaces by filtering the output.
R1# show ip interface brief | exclude unassigned Interface IP-Address OK? Method Status Protocol GigabitEthernet0/0/0 172.16.20.1 YES manual administratively down down GigabitEthernet0/0/1 172.16.20.129 YES manual up up Serial0/1/0 209.165.200.229 YES manual up up
b. Based on the output, correct any port status problems that you see.
GigabitEthernet0/0/0 is down, to enable it:
R1(config)#interface g0/0/0 R1(config-if)#no shutdown
c. Refer to the Addressing Table and verify the IP addresses configured on R1. Make any corrections to addressing if necessary.
R1#show running-config Building configuration... Current configuration : 977 bytes ! version 15.4 no service timestamps log datetime msec no service timestamps debug datetime msec no service password-encryption ! hostname R1 !
IP address and subnet mask interface Serial 0/1/0 incorrect, corrections it:
R1(config)#interface serial0/1/0 R1(config-if)#ip address 209.165.200.225 255.255.255.252
d. Display the routing table by filtering to start the output at the word Gateway.
Note: Terms that are used to filter output can be shortened to match text as long as the match is unique.
For example, Gateway, Gate, and Ga will have the same effect. G will not. Filtering is case-sensitive
R1# show ip route | begin Gate
Gateway of last resort is 209.165.200.226 to network 0.0.0.0
172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
C 172.16.20.0/25 is directly connected, GigabitEthernet0/0/0
L 172.16.20.1/32 is directly connected, GigabitEthernet0/0/0
C 172.16.20.128/25 is directly connected, GigabitEthernet0/0/1
L 172.16.20.129/32 is directly connected, GigabitEthernet0/0/1
209.165.200.0/24 is variably subnetted, 2 subnets, 2 masks
C 209.165.200.224/30 is directly connected, Serial0/1/0
L 209.165.200.225/32 is directly connected, Serial0/1/0
S* 0.0.0.0/0 [1/0] via 209.165.200.226
What is the Gateway of last resort address?
209.165.200.226
e. Display interface information and filter for Description or connected.
Note: When using include or exclude multiple searches can be performed by separating the search strings with a pipe symbol ( | )
R1# show interface | include Desc|conn
What is the Circuit ID displayed from your output?
BCB123450001
R1#show interface | include Desc|conn GigabitEthernet0/0/0 is up, line protocol is up (connected) Description: Connection to SW1 GigabitEthernet0/0/1 is up, line protocol is up (connected) Description: Connection to SW2 Serial0/1/0 is up, line protocol is up (connected) Description: Circuit ID BCB123450001 R1#
f. Display specific interface information for G0/0/0 by filtering for duplex.
What is the duplex setting, speed, and media type?
Full-duplex, 100Mb/s, media type is RJ45
R1#show interfaces gigabitEthernet 0/0/0 | include duplex Full-duplex, 100Mb/s, media type is RJ45
Step 2: Verify connectivity.
PC1 and PC2 should be able to ping each other and the Dual Stack Server. If not, verify the status of the interfaces and the IP address assignments.
Part 2: Verify IPv6 Directly Connected Networks
Step 1: Verify IPv6 addresses and port status on R2.
a. Check the status of the configured interfaces.
R2# show ipv6 int brief
What is the status of the configured interfaces?
All configured interfaces are up/up.
2#show ipv6 interface brief GigabitEthernet0/0/0 [up/up] FE80::2 2001:DB8:C0DE:12::1 GigabitEthernet0/0/1 [up/up] FE80::2 2001:DB8:C0DE:14::1 Serial0/1/0 [administratively down/down] unassigned Serial0/1/1 [up/up] FE80::2D0:BCFF:FE32:7C24 2001:DB8:C0DE:11::1 Vlan1 [administratively down/down] unassigned R2#
b. Refer to the Addressing Table and make any corrections to addressing as necessary.
Note: When changing an IPv6 address it is necessary to remove the incorrect address since an interface is capable of supporting multiple IPv6 networks.
R2(config)# int g0/0/1 R2(config-if)# no ipv6 address 2001:db8:c0de:14::1/64
Configure the correct address on the interface.
R2(config)#int g0/0/1 R2(config-if)#no ipv6 address 2001:DB8:C0DE:14::1/64 R2(config-if)#ipv6 address 2001:db8:c0de:13::1/64 R2(config-if)#exit R2(config)#int s0/1/1 R2(config-if)#no ipv6 address 2001:DB8:C0DE:11::1/64 R2(config-if)#ipv6 address 2001:db8:c0de:11::1/64 R2(config-if)#
c. Display the IPv6 routing table.
Note: Filtering commands do not presently work with the IPv6 commands.
R2#show ipv6 route
IPv6 Routing Table - 8 entries
Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP
U - Per-user Static route, M - MIPv6
I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary
O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
D - EIGRP, EX - EIGRP external
S ::/0 [1/0]
via Serial0/1/1, directly connected
C 2001:DB8:C0DE:11::/64 [0/0]
via Serial0/1/1, directly connected
L 2001:DB8:C0DE:11::1/128 [0/0]
via Serial0/1/1, receive
C 2001:DB8:C0DE:12::/64 [0/0]
via GigabitEthernet0/0/0, directly connected
L 2001:DB8:C0DE:12::1/128 [0/0]
via GigabitEthernet0/0/0, receive
C 2001:DB8:C0DE:13::/64 [0/0]
via GigabitEthernet0/0/1, directly connected
L 2001:DB8:C0DE:13::1/128 [0/0]
via GigabitEthernet0/0/1, receive
L FF00::/8 [0/0]
via Null0, received. Display all IPv6 addressing configured on interfaces by filtering the output of the running-config.
Filter the output on R2 for ipv6 or interface.
R2#show run | include ipv6|interface
ipv6 unicast-routing
no ipv6 cef
interface GigabitEthernet0/0/0
ipv6 address FE80::2 link-local
ipv6 address 2001:DB8:C0DE:12::1/64
ipv6 enable
interface GigabitEthernet0/0/1
ipv6 address FE80::2 link-local
ipv6 address 2001:DB8:C0DE:13::1/64
ipv6 enable
interface Serial0/1/0
interface Serial0/1/1
ipv6 address 2001:DB8:C0DE:11::1/64
ipv6 enable
interface Vlan1
ipv6 route ::/0 Serial0/1/1How many addresses are configured on each Gigabit interface?
There are 2 IPv6 addresses. The IPv6 /64 address and the IPv6 link-local address.
Step 2: Verify connectivity.
PC3 and PC4 should be able to ping each other and the Dual Stack Server. If not, verify the interface status and IPv6 address assignments.
Device Configs - Final
Issues Found and Solutions
Both routers are preconfigured, but three faults were introduced. Each one is found by reading the filtered show output described in the lab.
| # | Device | Issue | Solution |
|---|---|---|---|
| 1 | R1 — G0/0/0 | Interface is administratively down, so the PC1 LAN is unreachable | Apply no shutdown |
| 2 | R1 — S0/1/0 | Wrong IPv4 address 209.165.200.229 — this lands in the 209.165.200.228/30 subnet, so the default-route next hop 209.165.200.226 is unreachable |
Set it to 209.165.200.225 255.255.255.252 |
| 3 | R2 — G0/0/1 | Wrong IPv6 prefix 2001:db8:c0de:14::1/64 — PC4's LAN is 2001:db8:c0de:13::/64 |
Remove the wrong address, then apply 2001:db8:c0de:13::1/64 |
Why the serial address matters: a /30 has only two usable hosts. With 209.165.200.225, the subnet is 209.165.200.224/30 and the two hosts are .225 and .226 — so the gateway of last resort (.226) sits on the same link. With the faulty .229, the subnet becomes 209.165.200.228/30 (hosts .229 and .230), and .226 is no longer directly connected at all.
Fix on R1
! ============================================================== !--- 1.5.10 Packet Tracer - Verify Directly Connected Networks !--- FIX SCRIPT FOR ROUTER R1 !--- Usage: copy this whole file and paste it into the R1 terminal (start at the R1> prompt). The user EXEC password is "cisco" and the privileged EXEC password is "class". !--- This is a VERIFY / TROUBLESHOOT lab: the script applies only the corrective commands for the faults found with the show commands. ! ============================================================== enable configure terminal ! -------------------------------------------------------------- !--- Fault 1: G0/0/0 was administratively down, so the PC1 LAN (172.16.20.0/25) was unreachable. Found with: show ip interface brief | exclude unassigned ! -------------------------------------------------------------- !--- Bring the LAN interface back up. interface g0/0/0 no shutdown exit ! -------------------------------------------------------------- !--- Fault 2: S0/1/0 had the wrong IPv4 address (209.165.200.229 instead of 209.165.200.225), which put it in the wrong /30 subnet - the default route next hop 209.165.200.226 was therefore unreachable. ! -------------------------------------------------------------- !--- Correct the WAN address. On IPv4 the new primary address automatically replaces the old one, so no 'no ip address' is needed first. interface s0/1/0 ip address 209.165.200.225 255.255.255.252 no shutdown exit end ! -------------------------------------------------------------- !--- Save the configuration to NVRAM. (Press Enter when prompted.) ! -------------------------------------------------------------- copy running-config startup-config ! ============================================================== !--- Verification: !--- show ip interface brief | exclude unassigned -> all three interfaces up/up !--- show ip route | begin Gate -> Gateway of last resort is 209.165.200.226 !--- show interface | include Desc|conn -> descriptions and link state !--- show interface g0/0/0 | include duplex -> Full-duplex, 100Mb/s, RJ45 !--- From PC1 and PC2: ping each other and the Dual Stack Server. ! ==============================================================
Fix on R2
! ============================================================== !--- 1.5.10 Packet Tracer - Verify Directly Connected Networks !--- FIX SCRIPT FOR ROUTER R2 !--- Usage: copy this whole file and paste it into the R2 terminal (start at the R2> prompt). The user EXEC password is "cisco" and the privileged EXEC password is "class". !--- This is a VERIFY / TROUBLESHOOT lab: the script applies only the corrective commands for the faults found with the show commands. ! ============================================================== enable configure terminal ! -------------------------------------------------------------- !--- Fault 3: G0/0/1 had the wrong IPv6 prefix (2001:db8:c0de:14::1/64 instead of :13::1/64), so PC4's LAN did not match its gateway. Found with: show ipv6 interface brief ! -------------------------------------------------------------- !--- IMPORTANT: unlike IPv4, an interface can hold MULTIPLE IPv6 addresses - a new one does NOT replace the old one. The wrong prefix must be removed explicitly, or both will stay active. interface g0/0/1 no ipv6 address 2001:db8:c0de:14::1/64 !--- Apply the correct prefix from the Addressing Table. The link-local fe80::2 (PC4's default gateway) is already configured on this interface and is not affected. ipv6 address 2001:db8:c0de:13::1/64 no shutdown exit end ! -------------------------------------------------------------- !--- Save the configuration to NVRAM. (Press Enter when prompted.) ! -------------------------------------------------------------- copy running-config startup-config ! ============================================================== !--- Verification: !--- show ipv6 interface brief -> G0/0/1 shows 2001:DB8:C0DE:13::1 + FE80::2 !--- show ipv6 route -> the connected IPv6 LANs !--- show running-config | include ipv6|interface -> 2 addresses per Gigabit interface !--- From PC3 and PC4: ping each other and the Dual Stack Server. ! ==============================================================
Important IPv4 vs IPv6 difference: on an IPv4 interface, a new primary address automatically replaces the old one. On an IPv6 interface, an interface can hold multiple addresses, so the incorrect address must be removed explicitly with no ipv6 address — otherwise both prefixes stay active on the interface.
