Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A branch router uses PPP on a serial WAN link. Which additional PPP capability most directly improves access security on that link?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
PPP authentication
This is correct because peer authentication is a direct PPP security-related capability.
B
Distractor review
STP root election
This is wrong because STP is unrelated to serial PPP WAN authentication.
C
Distractor review
Wireless roaming
This is wrong because roaming is not a serial WAN authentication feature.
D
Distractor review
IPv6 loopback addressing
This is wrong because loopback addressing does not authenticate a PPP peer.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is selecting options like STP root election or IPv6 loopback addressing as security features for PPP links. STP is a Layer 2 protocol that prevents loops in Ethernet networks and does not apply to serial WAN links or PPP authentication. Similarly, IPv6 loopback addresses are used for router management and diagnostics, not for authenticating peers on a WAN link. Candidates may also be tempted by unrelated wireless concepts like roaming, which have no bearing on PPP serial link security. Recognizing that PPP authentication specifically addresses peer verification on point-to-point links is essential to avoid these distractions.
Technical deep dive
How to think about this question
Point-to-Point Protocol (PPP) is a data link layer protocol commonly used to establish direct connections between two networking nodes over serial links. One of PPP's key features is its support for authentication protocols such as PAP (Password Authentication Protocol) and CHAP (Challenge Handshake Authentication Protocol), which verify the identity of the connected peer before allowing network communication. This capability enhances security by preventing unauthorized devices from establishing a link. In Cisco environments, enabling PPP authentication on a serial WAN link requires configuring authentication methods on both ends of the link. This process ensures that the router verifies the identity of its peer before fully bringing up the link, thereby preventing unauthorized access and potential security breaches. Without authentication, PPP simply establishes a connection without validating the remote device, which can expose the network to risks. A common exam trap is confusing PPP authentication with unrelated concepts such as Spanning Tree Protocol (STP) or IPv6 addressing. While STP manages Layer 2 loop prevention and IPv6 loopback addresses serve diagnostic purposes, neither provides security for PPP links. Understanding that PPP authentication directly secures the link by verifying peer identity is crucial for correctly answering questions about WAN link security in the CCNA exam.
KKey Concepts to Remember
- PPP authentication verifies the identity of a peer before establishing a point-to-point WAN link, enhancing access security on serial connections.
- Cisco routers use PAP and CHAP as PPP authentication protocols to provide different levels of security and challenge-response mechanisms.
- Without PPP authentication, a serial WAN link can be established without validating the remote device, exposing the network to unauthorized access.
- STP root election manages Layer 2 loop prevention and does not influence PPP link security or authentication on serial WAN links.
- IPv6 loopback addresses serve diagnostic and management purposes and do not provide authentication or security for PPP links.
- PPP authentication must be configured on both ends of the WAN link to successfully verify peer identity and establish a secure connection.
- PPP authentication is an optional but important feature that distinguishes PPP from other WAN protocols that lack built-in authentication.
- Understanding the role of PPP authentication helps avoid confusing it with unrelated WAN or LAN technologies during CCNA exam scenarios.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
PPP authentication verifies the identity of a peer before establishing a point-to-point WAN link, enhancing access security on serial connections.
What is the correct answer to this question?
The correct answer is: PPP authentication — PPP authentication most directly improves access security on the link. In practical terms, authentication helps verify the identity of the peer rather than simply bringing up the point-to-point connection without validation. That makes PPP more useful than a bare unauthenticated link in environments where peer identity matters. At CCNA level, the important point is recognizing that PPP is associated with optional authentication capability on WAN links.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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