16.3.1 Packet Tracer – Troubleshoot Static and Default Routes – Instructions Answer

Last Updated: Oct 27, 2026 CCNA v7 Course #2, CCNA v7.0 1 Comment

16.3.1 Packet Tracer - Troubleshoot Static and Default Routes Answers

Topology

16.3.1 Packet Tracer – Troubleshoot Static and Default Routes

Addressing Table

Device Interface IP Addresses
R1 G0/0 172.31.1.1/25
2001:DB8:1::1/64
S0/0/0 172.31.1.194/30
2001:DB8:2::194/64
R2 G0/0 172.31.0.1/24
2001:DB8:3::1/64
S0/0/0 172.31.1.193/30
2001:DB8:2::193/64
S0/0/1 172.31.1.197/30
2001:DB8:4::197/64
R3 G0/0 172.31.1.129/26
2001:DB8:5::1/64
S0/0/1 172.31.1.198/30
2001:DB8:4::198/64
PC1 NIC 172.31.1.126/25
2001:DB8:1::126/64
PC2 NIC 172.31.0.254/24
2001:DB8:3::254/64
Server NIC 172.31.1.190/26
2001:DB8:5::190/64

Objectives

In this activity you will troubleshoot static and default routes and repair any errors that you find.

  • Troubleshoot IPv4 static routes.
  • Troubleshoot IPv4 default routes.
  • Troubleshoot IPv6 static routes.
  • Configure IPv4 static routes.
  • Configure IPv4 default routes.
  • Configure IPv6 static routes.

Background / Scenario

A newly hired network technician is attempting to preconfigure a simple topology that will be delivered to a customer. The technician has not been able to establish connectivity between the three LANs. You have been asked to troubleshoot the topology and verify connectivity between the hosts on the three LANs over IPv4 and IPv6.

Instructions

Step 1: Locate and document the problems.

Review the routing tables on R1, R2, and R3.

R1# show ip route
Codes: L - local, 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, E - EGP
       i - IS-IS, 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 172.31.1.195 to network 0.0.0.0

     172.31.0.0/16 is variably subnetted, 4 subnets, 3 masks
C       172.31.1.0/25 is directly connected, GigabitEthernet0/0
L       172.31.1.1/32 is directly connected, GigabitEthernet0/0
C       172.31.1.192/30 is directly connected, Serial0/0/0
L       172.31.1.194/32 is directly connected, Serial0/0/0
S*   0.0.0.0/0 [1/0] via 172.31.1.195

R1# 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
       ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
       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
C   2001:DB8:1::/64 [0/0]
     via GigabitEthernet0/0, directly connected
L   2001:DB8:1::1/128 [0/0]
     via GigabitEthernet0/0, receive
C   2001:DB8:2::/64 [0/0]
     via Serial0/0/0, directly connected
L   2001:DB8:2::194/128 [0/0]
     via Serial0/0/0, receive
S   2001:DB8:3::/64 [1/0]
     via Serial0/0/0, directly connected
S   2001:DB8:4::/64 [1/0]
     via Serial0/0/0, directly connected
S   2001:DB8:5::/64 [1/0]
     via Serial0/0/0, directly connected
L   FF00::/8 [0/0]
     via Null0, receive

R2# show ip route
Codes: L - local, 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, E - EGP
       i - IS-IS, 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

     172.31.0.0/16 is variably subnetted, 8 subnets, 5 masks
C       172.31.0.0/24 is directly connected, GigabitEthernet0/0
L       172.31.0.1/32 is directly connected, GigabitEthernet0/0
S       172.31.1.0/25 [1/0] via 172.31.1.198
S       172.31.1.128/26 [1/0] via 172.31.1.194
C       172.31.1.192/30 is directly connected, Serial0/0/0
L       172.31.1.193/32 is directly connected, Serial0/0/0
C       172.31.1.196/30 is directly connected, Serial0/0/1
L       172.31.1.197/32 is directly connected, Serial0/0/1

R2# show ipv6 route
IPv6 Routing Table - 9 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
       ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
       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   2001:DB6:1::/64 [1/0]
     via 2001:DB8:2::194
C   2001:DB8:2::/64 [0/0]
     via Serial0/0/0, directly connected
L   2001:DB8:2::193/128 [0/0]
     via Serial0/0/0, receive
C   2001:DB8:3::/64 [0/0]
     via GigabitEthernet0/0, directly connected
L   2001:DB8:3::1/128 [0/0]
     via GigabitEthernet0/0, receive
C   2001:DB8:4::/64 [0/0]
     via Serial0/0/1, directly connected
L   2001:DB8:4::197/128 [0/0]
     via Serial0/0/1, receive
S   2001:DB8:5::/64 [1/0]
     via 2001:DB8:4::198
L   FF00::/8 [0/0]
     via Null0, receive

R3# show ip route
Codes: L - local, 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, E - EGP
       i - IS-IS, 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

     172.31.0.0/16 is variably subnetted, 7 subnets, 5 masks
S       172.31.0.0/24 is directly connected, Serial0/0/1
S       172.31.1.0/28 is directly connected, Serial0/0/1
C       172.31.1.128/26 is directly connected, GigabitEthernet0/0
L       172.31.1.129/32 is directly connected, GigabitEthernet0/0
S       172.31.1.192/30 is directly connected, Serial0/0/1
C       172.31.1.196/30 is directly connected, Serial0/0/1
L       172.31.1.198/32 is directly connected, Serial0/0/1

R3# show ipv6 route
IPv6 Routing Table - 7 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
       ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
       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   2001:DB8:2::/64 [1/0]
     via Serial0/0/1, directly connected
S   2001:DB8:3::/64 [1/0]
     via Serial0/0/1, directly connected
C   2001:DB8:4::/64 [0/0]
     via Serial0/0/1, directly connected
L   2001:DB8:4::198/128 [0/0]
     via Serial0/0/1, receive
C   2001:DB8:5::/64 [0/0]
     via GigabitEthernet0/0, directly connected
L   2001:DB8:5::1/128 [0/0]
     via GigabitEthernet0/0, receive
L   FF00::/8 [0/0]
     via Null0, receive

Record your findings in a table like the one below.

Location Problem Solution
R1 The IPv4 default route next hop address is incorrect. Change the next hop address to 172.31.1.193.
R2 IPv6 route to LAN 1 has the wrong network address for the destination network. Change destination address from 2001:DB6:1::/64 to 2001:DB8:1::/64.
R2 The next hop addresses in the two IPv4 routes are reversed. Change the statements to ip route 172.31.1.0 255.255.255.128 172.31.1.194 and ip route 172.31.1.128 255.255.255.192 172.31.1.198.
R3 The IPv6 route to LAN 1 is missing. Configure a directly connected static route to 2001:DB8:1::/64.
R3 The IPv4 route to LAN 1 has the wrong mask for the network. Change the mask to 255.255.255.128.

Step 2: Repair the problems.

Configure the devices so that full connectivity exists between the hosts on the LANs over IPv4 and IPv6.

Note: Your task is to establish connectivity using the existing static route design. Changing the types of static routes used will result in a loss of points.

R1:

R1(config)# no ip route 0.0.0.0 0.0.0.0 172.31.1.195
R1(config)# ip route 0.0.0.0 0.0.0.0 172.31.1.193

R2:

R2(config)# no ip route 172.31.1.0 255.255.255.128 172.31.1.198
R2(config)# no ip route 172.31.1.128 255.255.255.192 172.31.1.194
R2(config)# ip route 172.31.1.0 255.255.255.128 172.31.1.194
R2(config)# ip route 172.31.1.128 255.255.255.192 172.31.1.198
R2(config)# no ipv6 route 2001:DB6:1::/64 2001:DB8:2::194
R2(config)# ipv6 route 2001:DB8:1::/64 2001:DB8:2::194

R3:

R3(config)# no ip route 172.31.1.0 255.255.255.240 Serial0/0/1
R3(config)# ip route 172.31.1.0 255.255.255.128 Serial0/0/1
R3(config)# ipv6 route 2001:DB8:1::/64 Serial0/0/1

Device Configs - Final

ROUTER R1

! ==============================================================
!--- 16.3.1 Packet Tracer - Troubleshoot Static and Default Routes
!--- FIX SCRIPT FOR ROUTER R1
!--- Usage: copy this whole file and paste it into the R1 terminal (start at the R1> prompt). Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Step 2: Repair the problems.
! --------------------------------------------------------------

!--- R1: the IPv4 default route points to 172.31.1.195 (broadcast address of the R1-R2 link). Remove it and use R2 S0/0/0 (172.31.1.193) as the next hop.
no ip route 0.0.0.0 0.0.0.0 172.31.1.195
ip route 0.0.0.0 0.0.0.0 172.31.1.193

end

! --------------------------------------------------------------
!--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config


! ==============================================================
!--- Verification:
!---   show ip route static    -> S* 0.0.0.0/0 [1/0] via 172.31.1.193
!---   From PC1, ping 172.31.0.254 and 172.31.1.190 -> success after R2 and R3 are also fixed
! ==============================================================

ROUTER R2

! ==============================================================
!--- 16.3.1 Packet Tracer - Troubleshoot Static and Default Routes
!--- FIX SCRIPT FOR ROUTER R2
!--- Usage: copy this whole file and paste it into the R2 terminal (start at the R2> prompt). Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Step 2: Repair the problems.
! --------------------------------------------------------------

!--- R2: the next hop addresses in the two IPv4 routes are reversed. Remove both wrong routes first.
no ip route 172.31.1.0 255.255.255.128 172.31.1.198
no ip route 172.31.1.128 255.255.255.192 172.31.1.194

!--- LAN 1 (172.31.1.0/25) via R1 S0/0/0; LAN 3 (172.31.1.128/26) via R3 S0/0/1.
ip route 172.31.1.0 255.255.255.128 172.31.1.194
ip route 172.31.1.128 255.255.255.192 172.31.1.198

!--- R2: the IPv6 route to LAN 1 uses the wrong destination network (2001:DB6:1::/64). Replace it with 2001:DB8:1::/64, keeping the same next hop.
no ipv6 route 2001:DB6:1::/64 2001:DB8:2::194
ipv6 route 2001:DB8:1::/64 2001:DB8:2::194

end

! --------------------------------------------------------------
!--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config


! ==============================================================
!--- Verification:
!---   show ip route static    -> 172.31.1.0/25 via 172.31.1.194, 172.31.1.128/26 via 172.31.1.198
!---   show ipv6 route         -> S 2001:DB8:1::/64 via 2001:DB8:2::194 (no 2001:DB6:1::/64 entry)
!---   From PC2, ping PC1 and the Server over IPv4 and IPv6 -> success after R1 and R3 are also fixed
! ==============================================================

ROUTER R3

! ==============================================================
!--- 16.3.1 Packet Tracer - Troubleshoot Static and Default Routes
!--- FIX SCRIPT FOR ROUTER R3
!--- Usage: copy this whole file and paste it into the R3 terminal (start at the R3> prompt). Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Step 2: Repair the problems.
! --------------------------------------------------------------

!--- R3: the IPv4 route to LAN 1 has the wrong mask (/28). Replace it with 255.255.255.128 (/25), keeping the directly connected design.
no ip route 172.31.1.0 255.255.255.240 Serial0/0/1
ip route 172.31.1.0 255.255.255.128 Serial0/0/1

!--- R3: the IPv6 route to LAN 1 is missing. Add a directly connected static route, like the other R3 IPv6 routes.
ipv6 route 2001:DB8:1::/64 Serial0/0/1

end

! --------------------------------------------------------------
!--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config


! ==============================================================
!--- Verification:
!---   show ip route static    -> 172.31.1.0/25 is directly connected, Serial0/0/1
!---   show ipv6 route         -> S 2001:DB8:1::/64 via Serial0/0/1, directly connected
!---   From the Server, ping PC1 and PC2 over IPv4 and IPv6 -> success after R1 and R2 are also fixed
! ==============================================================

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