Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
Which statement best describes the difference between PAP and CHAP in PPP authentication at a basic level?
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
CHAP is generally considered stronger than PAP for PPP authentication.
This is correct because CHAP is typically presented as the stronger authentication option.
B
Distractor review
PAP is required before CHAP can operate.
This is wrong because PAP is not a prerequisite for CHAP.
C
Distractor review
CHAP is used only on wireless guest SSIDs.
This is wrong because CHAP here refers to PPP authentication, not WLAN authentication.
D
Distractor review
PAP and CHAP are both STP guard features.
This is wrong because they are PPP authentication methods, not STP features.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is assuming PAP and CHAP are related to wireless authentication or STP features, which they are not. Another frequent mistake is believing PAP must be used before CHAP can operate, which is incorrect because they are independent PPP authentication methods. Candidates may also underestimate the security difference, thinking both protocols provide similar protection, when in fact PAP sends passwords in clear text, making it insecure. Misinterpreting these points can lead to incorrect answers about PPP authentication in Cisco exams.
Technical deep dive
How to think about this question
PPP (Point-to-Point Protocol) supports multiple authentication methods to verify the identity of connecting devices, with PAP (Password Authentication Protocol) and CHAP (Challenge Handshake Authentication Protocol) being the most common. PAP uses a simple two-way handshake where the username and password are sent in clear text, making it vulnerable to interception. CHAP, on the other hand, uses a three-way handshake involving a challenge and a hashed response, which protects credentials from being sent in clear text and allows repeated authentication during a session. In Cisco networking and the CCNA context, CHAP is preferred over PAP because it provides stronger security by periodically verifying the identity of the peer using a shared secret and a challenge-response mechanism. This makes CHAP resistant to replay attacks and eavesdropping, whereas PAP’s simple transmission of credentials is easily compromised. Understanding this difference helps CCNA candidates recognize why CHAP is generally recommended for PPP authentication in real-world network deployments. A common exam trap is confusing PAP and CHAP with unrelated technologies or features, such as wireless authentication methods or Spanning Tree Protocol (STP) features. Candidates might also mistakenly believe that PAP must precede CHAP or that both are equally secure. In practice, CHAP’s challenge-response mechanism provides ongoing verification, making it more secure and suitable for Cisco PPP links, while PAP’s simplicity limits its use to less secure or legacy environments.
KKey Concepts to Remember
- PPP authentication supports PAP and CHAP as two distinct methods for verifying peer identity during link establishment.
- PAP transmits credentials in clear text using a simple two-way handshake, making it vulnerable to interception and replay attacks.
- CHAP uses a three-way handshake with a challenge and hashed response, providing stronger security by not sending passwords in clear text.
- Cisco devices prefer CHAP over PAP for PPP authentication due to CHAP’s ability to periodically re-authenticate peers during a session.
- PAP is not a prerequisite for CHAP; they operate independently as alternative authentication protocols within PPP.
- CHAP’s challenge-response mechanism helps prevent replay attacks and ensures ongoing verification of the peer’s identity.
- Neither PAP nor CHAP are related to Spanning Tree Protocol (STP) or wireless guest SSID authentication methods.
- Understanding the security differences between PAP and CHAP helps CCNA candidates select appropriate PPP authentication methods.
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 supports PAP and CHAP as two distinct methods for verifying peer identity during link establishment.
What is the correct answer to this question?
The correct answer is: CHAP is generally considered stronger than PAP for PPP authentication. — At a basic level, CHAP is generally considered stronger than PAP because it does not rely on the same simple approach to credential exchange. In practical terms, CCNA learners should recognize that PPP supports authentication options and that CHAP is typically the more security-conscious choice compared with PAP. The point is not to memorize every exchange sequence, but to understand that the two methods are not equally strong.
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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