Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
Which statement best describes why source restriction does not replace the need for strong authentication?
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
Because an allowed source location does not prove the identity of the person or system using it.
This is correct because source restriction narrows origin, while authentication verifies identity.
B
Distractor review
Because source restriction works only on IPv6 and authentication works only on IPv4.
This is wrong because both concepts apply broadly.
C
Distractor review
Because authentication can be used only after OSPF adjacency forms.
This is wrong because administrative authentication is not dependent on OSPF.
D
Distractor review
Because source restriction automatically logs all device changes.
This is wrong because source filtering does not replace logging.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is to confuse source restriction with authentication, assuming that limiting access by IP address is enough to verify identity. This mistake overlooks that source restriction only controls where traffic comes from, not who is behind it. Attackers can spoof allowed IP addresses or gain access from within trusted networks, bypassing source-based controls. The trap is to think that source restriction replaces the need for strong authentication, which actually verifies user or device credentials and is essential for secure network management.
Technical deep dive
How to think about this question
Source restriction is a network security control that limits access based on the origin IP address or subnet. It is commonly implemented using access control lists (ACLs) or firewall rules to permit or deny traffic from specific source addresses. While this reduces exposure to unauthorized networks, it does not confirm the identity of the user or device initiating the connection. This distinction is critical because IP addresses can be spoofed or shared among multiple users, making source restriction an incomplete security measure on its own. Strong authentication, on the other hand, requires users or devices to prove their identity through credentials such as passwords, digital certificates, or multi-factor authentication methods. In Cisco environments, protocols like TACACS+ and RADIUS are used to authenticate administrative access to network devices, ensuring that only authorized personnel can make configuration changes. This identity verification step is essential because it prevents unauthorized users from exploiting trusted source locations to gain access. The exam trap lies in assuming that source restriction alone is sufficient for security. While source filtering narrows the attack surface by blocking traffic from untrusted networks, it does not prevent internal threats or credential compromise. In practical Cisco network management, combining source restriction with strong authentication creates a layered defense that verifies both the origin and the identity of connections. This layered approach aligns with best practices for securing the management plane and protecting network infrastructure from unauthorized access.
KKey Concepts to Remember
- Source restriction limits network access based on IP addresses or source locations but does not verify the identity of the user or device behind the connection.
- Strong authentication verifies the identity of a user or device through credentials such as passwords, certificates, or tokens, ensuring authorized access beyond just source location.
- In Cisco network security, administrative controls like source restriction and authentication work together to provide layered defense rather than replacing each other.
- Source restriction can help reduce attack surface by filtering traffic from unauthorized IP ranges but cannot prevent credential misuse or insider threats.
- Authentication mechanisms such as 802.1X, TACACS+, or RADIUS provide identity verification that source-based filtering alone cannot achieve.
- Relying solely on source restriction risks unauthorized access if an attacker spoofs an allowed IP address or gains access from within the trusted network segment.
- Cisco devices enforce authentication before granting management-plane access, ensuring that only verified identities can configure or monitor network equipment.
- Effective network security design combines source restriction with strong authentication to control both where connections originate and who is allowed to connect.
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?
Source restriction limits network access based on IP addresses or source locations but does not verify the identity of the user or device behind the connection.
What is the correct answer to this question?
The correct answer is: Because an allowed source location does not prove the identity of the person or system using it. — Source restriction does not replace strong authentication because knowing where a connection comes from is not the same as knowing who is actually using it. In practical terms, an allowed source network may still contain unauthorized users or compromised devices. Authentication is still needed to verify identity. These controls complement one another rather than replacing one another. This is an important management-plane security concept because it emphasizes layered control rather than false trade-offs.
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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