You must configure and troubleshoot 802.1X, MAC RADIUS, and captive portal on EX Series switches, including RADIUS attributes and access profiles. The critical thing is to correctly interpret RADIUS attributes like Tunnel-Medium-Type and set authentication-order and server-timeout appropriately.
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Domain overview
This domain covers Layer 2 authentication and access control on Juniper EX Series switches, including 802. 1X, MAC RADIUS, captive portal, and RADIUS attributes. It tests your ability to configure access profiles, authentication order, and dynamic VLAN assignment, and to troubleshoot authentication flows using Junos CLI commands and server interactions.
Exam objectives
Configuring 802.1X authentication with RADIUS server attributes like Tunnel-Medium-Type and Tunnel-Type
Using access profiles to set server-timeout and authentication-order on EX Series interfaces
Implementing captive portal with pre-authentication access lists for management and server subnets
Verifying authentication sessions and troubleshooting with show dot1x and show network-access commands
Confusing Tunnel-Medium-Type (Attribute 65) with Tunnel-Type (Attribute 64); the former specifies the medium (e.g., IEEE-802), not the VLAN.
Assuming server-timeout defines the interval between retries; it actually sets how long the switch waits for a RADIUS server response before trying the next server.
Forgetting that captive portal pre-authentication access lists must be applied to the interface to allow management traffic before authentication.
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What is the primary function of the RADIUS server attribute 'Tunnel-Medium-Type' (Attribute 65) when received during an 802.1X authentication exchange on an EX Series switch?
2Which command allows an administrator to verify the active supplicant states and authentication status on a specific EX Series switch interface?
3An enterprise network administrator needs to configure 802.1X authentication on EX Series switches. Which statement is correct regarding the default behavior of the supplicant timeout timer?
4You are configuring a captive portal on an EX Series switch. You want to ensure that specific management traffic and critical server subnets are accessible to clients *before* they authenticate through the captive portal. Which configuration feature accomplishes this?
5Which statement accurately describes the function of the 'server-timeout' setting within a Juniper access profile?
6An EX Series switch is configured with 802.1X and MAC RADIUS. A client device connects that does not support 802.1X. The switch attempts 802.1X, times out, and successfully falls back to MAC RADIUS. However, the administrator notices a significant delay (several seconds) before the MAC RADIUS request is sent to the server. What parameter should be tuned to reduce this delay?
7What is the default authentication order when authentication is enabled on an EX Series switch interface without explicit ordering configuration?
8An EX4300 switch is configured with captive portal authentication. Unauthenticated users are successfully redirected when attempting HTTP traffic, but HTTPS traffic fails to redirect properly and instead shows a certificate warning or connection timeout in the user's browser. What is the fundamental reason for this behavior with standard captive portal implementations?
9You are troubleshooting an issue where an 802.1X supplicant on a Windows client fails to connect to an EX Series switch port. The switch logs show 'EAPOL-TIMEOUT' errors. What does this error indicate?
10Which RADIUS attribute is commonly used to assign a specific session timeout value to an 802.1X authenticated client on an EX Series switch?
11Which statement is true regarding the behavior of the supplicant mode 'single' on an EX Series switch port?
12An enterprise network uses 802.1X authentication with dynamic VLAN assignment on EX Series switches. A client authenticates, and the RADIUS server returns both a VLAN name and a set of dynamic firewall filter names via RADIUS attributes (Filter-Id). When the client connects, the VLAN assignment works perfectly, but the firewall filters are not applied to the interface. What is the most likely cause?
13Which TWO statements are correct regarding the behavior and configuration of multi-supplicant mode on EX Series switches? (Choose two)
14Which TWO actions occur when an 802.1X supplicant fails authentication and a guest VLAN is configured on the EX Series switch port? (Choose two)
15Which TWO options are valid authentication methods that can be specified in the 'authentication-order' statement on an EX Series switch interface? (Choose two)
16Which THREE parameters must be configured when implementing captive portal on an EX Series switch? (Choose three)
17Which TWO statements are correct regarding captive portal redirection behavior on EX Series switches? (Choose two)
18Which TWO options are valid configurable parameters under an access profile in Junos OS? (Choose two)
19Which THREE statements describe the behavior of critical authentication (fallback) when a RADIUS server becomes unreachable on an EX Series switch? (Choose three)
20You are deploying 802.1X on an EX Series switch. The security team requires that if the RADIUS server is unreachable during authentication, endpoints that were previously authenticated on a port must not lose network access, but new endpoints must be denied. Which action should you configure under the authenticator's interface to meet this requirement?
21You are deploying 802.1X on an EX4300 access port facing a conference room. The security team wants to prevent a user from unplugging an authenticated IP phone and plugging in an unauthorized laptop on the same port. You configure MACsec on the port. Which statement describes the security benefit that MACsec provides in this scenario?
22You are troubleshooting an EX Series switch where 802.1X authentication is failing for all users. The RADIUS server is reachable and the shared secret matches. Users report that authentication never completes and the switch logs show EAPOL exchanges starting but no Access-Request being sent. Which Junos command should you use to view the current 802.1X authentication state and counters on the interface?
23You are enabling 802.1X on an EX Series switch. You want to allow a PC that does not support 802.1X to access the network after a user opens a web browser and authenticates. Which feature should you configure on the switch?
24You are deploying 802.1X on an EX Series switch and want to ensure that when a supplicant fails authentication, it is placed into a VLAN that provides limited access to a remediation server. Which TWO Junos configuration elements are required to support this behavior? (Choose two.)
25You are configuring captive portal on an EX Series switch. Users must be redirected to an external web server for authentication. You have configured the captive portal profile with the redirect URL. However, users are not being redirected and can access the Internet without authentication. Which configuration issue is most likely?
26You are configuring an EX Series switch to support 802.1X authentication with multiple supplicants on a single interface. A hub connects three devices to interface ge-0/0/5. You want each device to be authenticated individually and placed into its assigned VLAN. Which configuration is required to support this?
27You are configuring an EX Series switch to authenticate users via 802.1X. The RADIUS server returns a Filter-Id attribute of 'student-acl' in the Access-Accept. You want the switch to apply a firewall filter named 'student-acl' to the authenticated user's traffic. Which configuration is required on the switch?
You must configure and troubleshoot 802.1X, MAC RADIUS, and captive portal on EX Series switches, including RADIUS attributes and access profiles. The critical thing is to correctly interpret RADIUS attributes like Tunnel-Medium-Type and set authentication-order and server-timeout appropriately.
The Courseiva JNCIP-ENT question bank contains 27 questions in the Layer 2 Authentication And Access Control domain. Click any question to see the full explanation and answer breakdown.
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