100-150 · domain
Security
The Security domain of the Cisco Certified Support Technician - Networking (100-150) exam covers foundational network defense concepts: threat mitigation for email and web traffic, Layer 2 attack prevention, ACL filtering on router interfaces, and the AAA framework. Questions are scenario-based, asking you to select the best Cisco feature or identify the purpose of a security control rather than configure it.
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What to know about Security
You must be able to match a stated threat to the correct Cisco security feature and explain what each control does. The most important thing to get right is the AAA distinction: Authentication verifies identity, Authorization grants permissions, and Accounting records activity for auditing.
Email and web security controls such as email filtering, web filtering, and endpoint antivirus protection
VLAN hopping prevention using native VLAN changes and disabling unused ports or trunk negotiation
Access Control Lists on Cisco router interfaces to filter traffic and enforce permitted or denied flows
The AAA framework: Authentication, Authorization, and Accounting, including the goal of accounting logs
Watch out for
Common Security exam traps
- ▸Confusing authentication with authorization, or assuming Accounting blocks access rather than recording user activity for auditing and billing.
- ▸Believing an ACL encrypts traffic or provides antivirus protection, when it only permits or denies packets based on defined criteria.
- ▸Thinking VLAN hopping is stopped by a single measure, when it requires changing the native VLAN and disabling unused ports or DTP.
Question index
All Security questions (53)
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A network administrator needs to prevent unauthorized devices from connecting to switch ports. Which feature provides the most effective Layer 2 security by verifying the MAC address of the connected device against a database?
Medium2Which security threat involves an attacker sending unsolicited and massive amounts of traffic to a network service to make it unavailable to legitimate users?
Medium3An employee receives an email that appears to be from the company's IT department, requesting their login credentials to perform an urgent system update. What type of social engineering attack does this represent?
Easy4What is the primary function of a firewall when placed at the edge of a network?
Easy5A small business owner wants to ensure that internal financial records are only viewed by authorized management personnel. Which pillar of the CIA triad is primarily addressed by implementing restricted folder permissions and encryption for these files?
Easy6Which Cisco feature is used to prevent Man-in-the-Middle attacks that rely on corrupting the ARP cache of connected hosts?
Medium7A security administrator is reviewing logs and notices that an attacker on the internal network is sending forged ARP replies claiming to be the default gateway. The attacker's goal is to intercept traffic from multiple hosts. The switches in the network already have DHCP snooping enabled on the user VLAN. Which additional Cisco feature should the administrator enable to block the forged ARP replies?
Hard8A network administrator needs to implement a VPN solution. Which TWO types of VPNs are commonly used in enterprise environments? (Choose TWO).
Medium9A company requires employees to use both a password and a one-time code sent to their mobile device to access the corporate VPN. Which security concept is being implemented?
Easy10An attacker on the same subnet sends frames with forged source MAC addresses to overwhelm a switch's MAC address table, causing the switch to flood unicast traffic out all ports. Which switch feature should be enabled to prevent this behavior on access ports?
Medium11Which port security violation mode will drop packets from an unauthorized MAC address, increment the security violation counter, and send a syslog message, but will not shut down the interface?
Medium12A user discovers that all their files have been encrypted and a message is displayed demanding payment in exchange for the decryption key. What type of malware has infected the system?
Easy13A network engineer is hardening a new Cisco switch that will be deployed in a lobby area accessible to visitors. The engineer wants to protect against MAC flooding attacks and against unauthorized devices connecting to access ports. Which two measures should the engineer implement? (Choose two.)
Medium14Which TWO of the following are valid methods for securing the administrative access of a Cisco device?
Hard15Which of the following describes the primary purpose of a security policy in a network environment?
Easy16A network administrator is configuring a Cisco switch and wants to ensure that only the designated uplink port can send DHCP server replies, while all other ports are prevented from acting as DHCP servers. Which command should be applied to the uplink port?
Medium17A small office has a single Cisco wireless router providing both employee and guest access. The manager wants guests to reach the internet but must not be able to reach the internal file server or the printer on the office LAN. Which feature should be enabled on the wireless router to meet this requirement?
Easy18A security team wants to protect users who connect laptops to the corporate wireless network from attackers who set up a nearby access point broadcasting the same SSID with a stronger signal. The requirement is that clients authenticate the network before associating and that the credentials never traverse the wireless medium in a recoverable form. Which technology satisfies these requirements?
Hard19A network administrator at a small clinic wants to prevent unauthorized users from plugging a personal laptop into an unused wall jack in the waiting room and obtaining an IP address on the internal VLAN. The clinic uses a Cisco Catalyst switch with 802.1X-capable access ports and a RADIUS server. Which solution best meets this requirement?
Medium20A user at a branch office receives a phone call from someone claiming to be a help desk technician. The caller already knows the user's employee ID, manager's name, and the model of laptop issued to the user, and asks the user to read back the six-digit code that was just texted to their phone so the technician can 'verify the device.' The user complies, and minutes later the attacker logs into the corporate VPN using the user's credentials. Which type of attack has occurred?
Easy21A network technician is reviewing a Cisco switch configuration and sees that PortFast and BPDU Guard are enabled on an access port that connects to a user's desktop. The user calls and reports that they accidentally plugged a small unmanaged switch into that wall jack so they could connect both a PC and a printer. Shortly afterward, the port stopped forwarding traffic. What is the most likely explanation for this behavior?
Medium22A company issues employees corporate laptops that contain confidential project data. The security policy requires that if a laptop is lost or stolen, the data on its drive cannot be read even if the disk is removed and attached to another computer. Which control should be implemented?
Hard23Refer to the exhibit. Why is the interface fa0/1 currently in the 'Secure-shutdown' state?
Hard24A company wants to prevent unauthorized individuals from entering the server room by following closely behind an employee. Which physical security control is specifically designed to address this risk?
Easy25A network administrator wants to prevent users on the corporate LAN from connecting unauthorized wireless access points and switches to wall jacks in conference rooms. The administrator needs a feature that restricts which MAC addresses are allowed to send traffic on each access port. Which Cisco switch feature should be configured?
Medium26Which of the following is a primary goal of the 'Accounting' component in the AAA security framework?
Easy27A help desk technician receives a call from an employee who says they received a text message claiming to be from the bank's fraud department, asking them to click a link and confirm their online banking password. The employee has not clicked the link. Which type of attack is this?
Easy28A company's IT policy states that only members of the finance group may access the payroll application, and that all access to it must be logged. A technician is asked to enforce this at the network level. Which concept does this requirement primarily describe?
Easy29Refer to the exhibit. What is the expected behavior if a second device with a different MAC address is plugged into this port?
Hard30A user at a branch office reports that when they browse to their bank's website, the browser displays a certificate warning and the address bar shows a lock with a red line through it. The help desk confirms the user's PC has the correct date and time. Which security concept is MOST likely being violated in this scenario?
Easy31A technician is configuring DHCP snooping on a Cisco switch to prevent rogue DHCP servers. On which type of port should the technician apply the 'ip dhcp snooping trust' command?
Medium32A small office wants to keep its wireless network traffic private so that neighbors cannot read the data being transmitted. Which technology should be enabled on the wireless access point to encrypt traffic between clients and the access point?
Easy33A company wants to ensure that even if an attacker steals a user's password, the attacker cannot log in without a second factor. Which authentication approach best meets this requirement?
Medium34A network administrator needs to prevent unauthorized devices from connecting to a switch port while ensuring that only a specific workstation can access the network. Which security feature should be implemented?
Medium35Which THREE features are introduced or enhanced in WPA3 to improve wireless security compared to WPA2? (Choose THREE).
Hard36An organization wants to implement a security policy that requires users to authenticate against a centralized server before gaining network access. Which protocol provides the necessary AAA framework to achieve this?
Medium37A network administrator is reviewing a Cisco switch configuration and sees that a port in the employee area has been configured with the 'switchport port-security' command and a maximum of one MAC address. A user unplugs their laptop and connects a different laptop to the same port. Assuming the default violation mode, what happens?
Medium38A network technician is selecting devices to protect a corporate network from external threats. Which TWO devices provide active threat mitigation by inspecting and blocking malicious traffic? (Choose TWO).
Medium39A security analyst notices that an attacker on the same VLAN as a user is sending forged ARP replies so that the user's traffic to the default gateway is redirected through the attacker's workstation. The switch is a Cisco Catalyst with DHCP snooping already configured and working. Which feature should the analyst enable to block this specific attack?
Hard40Refer to the exhibit. What is the result of applying this ACL to a router interface, and what is its implication for other traffic?
Hard41A small office wants to reduce the risk of malware arriving through email and malicious websites while keeping administration simple. Which two measures provide the strongest protection against these threats? (Choose two.)
Medium42Which THREE of the following are considered best practices for hardening a Cisco network device?
Medium43Which feature is best suited to prevent VLAN hopping attacks where an attacker sends double-tagged 802.1Q frames to reach a restricted VLAN?
Medium44Which TWO of the following are primary security benefits of implementing an Access Control List (ACL) on a Cisco router interface?
Medium45Refer to the exhibit. What is the effect of the 'ip dhcp snooping trust' command on the designated interface?
Medium46Which TWO methods are considered effective for securing the control plane of Cisco networking devices? (Choose two.)
Medium47Which component of the AAA security framework is responsible for determining which specific commands a user is permitted to execute on a Cisco router after they have successfully logged in?
Medium48A network team is hardening a Cisco Catalyst switch that will be deployed at the edge of the corporate network. They want to reduce the risk of Layer 2 attacks such as MAC flooding and unauthorized device attachment. Which two actions should they take? (Choose two.)
Medium49Which security feature is used to mitigate DHCP starvation attacks by limiting the number of DHCP messages per port?
Medium50A security team is reviewing how to protect a small office network from common Layer 2 attacks. The team wants to implement features that specifically prevent MAC address table overflow and ARP cache poisoning. Which two Cisco switch features should the team deploy? (Choose two.)
Medium51Which protocol is recommended for secure remote management of Cisco network devices over insecure networks?
Easy52An administrator wants to ensure that only legitimate DHCP servers provide IP addresses to clients on the network. Which feature should be enabled?
Medium53A network administrator must ensure that only specific management stations can reach the management VLAN on a Cisco switch, while ordinary user traffic on other VLANs flows unrestricted. The administrator wants a mechanism that filters traffic based on source IP addresses and can log denied attempts. Which feature should be configured?
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Frequently asked questions
- What does the Security domain cover on the 100-150 exam?
- You must be able to match a stated threat to the correct Cisco security feature and explain what each control does. The most important thing to get right is the AAA distinction: Authentication verifies identity, Authorization grants permissions, and Accounting records activity for auditing.
- How many questions are in this domain?
- This page lists all 53 Security questions in the 100-150 question bank. The actual exam draws from this domain proportionally to its weighting in the official exam blueprint.
- What is the best way to practise this domain?
- Start with a short focused session (10 questions) to identify gaps, then work through explanations. Repeat with a longer session once the weak areas feel solid.
- Can I practise only Security questions?
- Yes — the session launcher on this page filters questions to this domain only. Choose any session length for inline explanations and scoring.