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CCNA Network Infrastructure and Connectivity Practice Question

Exhibit

R1# show running-config | section interface
interface GigabitEthernet0/0
 ip address 192.168.1.1 255.255.255.0
 no shutdown
!
interface GigabitEthernet0/1
 no ip address
 ipv6 address 2001:db8:acad:1::/64 eui-64
 no shutdown
!
interface GigabitEthernet0/2
 ip address 10.0.0.1 255.255.255.252
 no shutdown
!

R1# show ip interface brief
Interface              IP-Address      OK? Method Status                Protocol
GigabitEthernet0/0     192.168.1.1     YES manual up                    up
GigabitEthernet0/1     unassigned      YES manual up                    up
GigabitEthernet0/2     10.0.0.1        YES manual up                    up

R1# show ipv6 interface brief
GigabitEthernet0/1     [up/up]
    FE80::/10
    2001:DB8:ACAD:1:20C:29FF:FE12:3456

R1# ping 203.0.113.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 203.0.113.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

R1# ping 2001:db8:acad:2::1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2001:DB8:ACAD:2::1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

(Information: R2's loopback is 203.0.113.1/32 reachable via R2's G0/0 192.168.1.2/24. R3's G0/0 is 2001:db8:acad:2::1/64, R3's G0/0 link-local is FE80::2.)

You are connected to R1 via the console. R1 has two directly connected routers: R2 and R3. Currently, R1 cannot reach R2's loopback interface (203.0.113.1/32). Additionally, R3 is IPv6-only and must be reachable from R1 using a statically assigned global unicast address. Configure R1's interfaces and static routes so that: (1) R1 can ping R2's loopback, (2) R1 can ping R3's IPv6 address 2001:db8:acad:2::1/64, and (3) R1's IPv6 address on the link to R3 is derived using EUI-64.

⚠ Common exam trap

Watch out for subnet mismatches in IPv6 and the requirement to use EUI-64. Many candidates forget that EUI-64 requires the 'eui-64' keyword, not a manual interface ID. Also, ensure static routes point to the exact host (/32) when the destination is a loopback.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

Configure R1's G0/0 with IP 192.168.1.1/24 and add a static route to 203.0.113.1/32 via 192.168.1.2. Configure R1's G0/1 with IPv6 address 2001:db8:acad:2::/64 eui-64.

The ping to R2's loopback fails because R1's G0/0 is configured with a /24 mask, but the network should be /24 (which is correct), but the loopback is on a different subnet (203.0.113.0/24 vs 192.168.1.0/24). Actually the issue is that R1 has no route to 203.0.113.1. The solution is to add a static route on R1 pointing to R2's G0/0 IP. For IPv6, R1's EUI-64 address is on the wrong subnet (2001:db8:acad:1::/64) but R3 is on 2001:db8:acad:2::/64. The fix is to change the IPv6 address on R1's G0/1 to 2001:db8:acad:2::/64 eui-64. Then add an IPv6 static route if needed (but R1 and R3 are directly connected, so after fixing the subnet, ping should work).

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • ✓

    Configure R1's G0/0 with IP 192.168.1.1/24 and add a static route to 203.0.113.1/32 via 192.168.1.2. Configure R1's G0/1 with IPv6 address 2001:db8:acad:2::/64 eui-64.

    Why this is correct

    Ly addresses both issues. The static route to R2's loopback (203.0.113.1/32) via next-hop 192.168.1.2 enables reachability. For IPv6, configuring G0/1 with the correct subnet (2001:db8:acad:2::/64) and using EUI-64 ensures R1 can ping R3's IPv6 address on the same subnet.

  • ✗

    Configure R1's G0/0 with IP 192.168.1.1/24 and add a static route to 203.0.113.0/24 via 192.168.1.2. Configure R1's G0/1 with IPv6 address 2001:db8:acad:1::/64 eui-64.

    Why it's wrong here

    This is incorrect because the static route to 203.0.113.0/24 is too broad; it would work but the question specifies the loopback is a /32. More critically, the IPv6 address is on subnet 2001:db8:acad:1::/64, which is not the same as R3's subnet (2001:db8:acad:2::/64), so R1 cannot ping R3 directly.

  • ✗

    Configure R1's G0/0 with IP 192.168.1.1/24 and add a static route to 203.0.113.1/32 via 192.168.1.2. Configure R1's G0/1 with IPv6 address 2001:db8:acad:2::1/64.

    Why it's wrong here

    This is incorrect because the IPv6 address on G0/1 is manually configured as 2001:db8:acad:2::1/64, which does not use EUI-64 as required. EUI-64 derives the interface ID from the MAC address, so the address must be configured with the eui-64 keyword.

  • ✗

    Configure R1's G0/0 with IP 192.168.1.1/24 and add a static route to 203.0.113.1/32 via 192.168.1.2. Configure R1's G0/1 with IPv6 address 2001:db8:acad:1::/64 eui-64.

    Why it's wrong here

    The IPv4 configuration and static route in this option are correct: R1's G0/0 addresses R2, and the /32 static route to 203.0.113.1 via 192.168.1.2 ensures reachability to R2's loopback. The IPv6 error is the subnet prefix: R1's G0/1 is placed in 2001:db8:acad:1::/64, but R3's IPv6 address is on 2001:db8:acad:2::/64, so the two interfaces are on different Layer 3 subnets. Even though the eui-64 keyword correctly derives the interface identifier from the MAC address, the address still belongs to the wrong network, so R1 cannot direct-ping R3; absent an IPv6 route to 2001:db8:acad:2::/64, no path exists.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.

✓Configure R1's G0/0 with IP 192.168.1.1/24 and add a static route to 203.0.113.1/32 via 192.168.1.2. Configure R1's G0/1 with IPv6 address 2001:db8:acad:2::/64 eui-64.Correct answer▾

Why this is correct

Ly addresses both issues. The static route to R2's loopback (203.0.113.1/32) via next-hop 192.168.1.2 enables reachability. For IPv6, configuring G0/1 with the correct subnet (2001:db8:acad:2::/64) and using EUI-64 ensures R1 can ping R3's IPv6 address on the same subnet.

✗Configure R1's G0/0 with IP 192.168.1.1/24 and add a static route to 203.0.113.0/24 via 192.168.1.2. Configure R1's G0/1 with IPv6 address 2001:db8:acad:1::/64 eui-64.Wrong answer — click to see why▾

Why this is wrong here

The IPv6 subnet mismatch prevents direct connectivity; R1 and R3 must be on the same subnet for a ping to work without additional routing.

Why candidates choose this

Candidates might think any /64 subnet works or that the static route to the loopback should match the network prefix rather than the host address.

✗Configure R1's G0/0 with IP 192.168.1.1/24 and add a static route to 203.0.113.1/32 via 192.168.1.2. Configure R1's G0/1 with IPv6 address 2001:db8:acad:2::1/64.Wrong answer — click to see why▾

Why this is wrong here

The requirement explicitly states that the IPv6 address must be derived using EUI-64; a manually specified interface ID violates this.

Why candidates choose this

Candidates may think that any valid IPv6 address on the correct subnet satisfies the requirement, overlooking the EUI-64 specification.

✗Configure R1's G0/0 with IP 192.168.1.1/24 and add a static route to 203.0.113.1/32 via 192.168.1.2. Configure R1's G0/1 with IPv6 address 2001:db8:acad:1::/64 eui-64.Wrong answer — click to see why▾

Why this is wrong here

The IPv6 subnet must be the same as R3's for direct connectivity; using a different subnet requires additional routing, which is not configured.

Why candidates choose this

Candidates might confuse the subnet for R1's link to R3 with another subnet or think EUI-64 automatically ensures reachability regardless of subnet.

Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

Visual reference

192.168.1.0 /24 256 addresses (254 usable) 192.168.1.0 /25 Subnet A 128 addr (126 usable) 192.168.1.128 /25 Subnet B 128 addr (126 usable) Borrowing 1 bit from host portion creates 2 subnets (/25)

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JA

Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.