PCNSE Practice Question: Securing Users and Applications with Authentication

Exhibit

Refer to the exhibit.

admin@PA-5000# show shared authentication-profile TestAuth
{
  "entry": {
    "@name": "TestAuth",
    "method": {
      "kerberos": {
        "server-profile": "KDC-Profile",
        "realm": "EXAMPLE.COM"
      },
      "allow-list": ["EXAMPLE\\user1", "EXAMPLE\\user2"]
    },
    "user-domain": "EXAMPLE",
    "expiration": 60
  }
}

An administrator configured the authentication profile shown. Users in the domain 'EXAMPLE' are unable to authenticate; logs show 'Authentication failed: user not found'. What is the likely issue?

⚠ Common exam trap

Watch out — candidates often assume 'user not found' always indicates a domain or Kerberos misconfiguration, overlooking the allow-list feature that explicitly blocks users not listed.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

The 'allow-list' is restricting authentication to only user1 and user2

The authentication profile includes an 'allow-list' that explicitly restricts authentication to only 'user1' and 'user2'. When a user from the 'EXAMPLE' domain attempts to authenticate, the firewall checks the allow-list first; since the user is not in that list, the authentication fails with the 'user not found' error, even if the user exists in the domain.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✓
The 'allow-list' is restricting authentication to only user1 and user2
Why this is correct
Only those two users are allowed; others are denied.
✗
The Kerberos server profile 'KDC-Profile' is misconfigured
Why it's wrong here
The error is 'user not found', not server unreachable.
✗
The expiration time of 60 minutes is too short
Why it's wrong here
Expiration time does not cause authentication failure.
✗
The realm 'EXAMPLE.COM' does not match the domain 'EXAMPLE'
Why it's wrong here
Domain and realm can be different; the configuration uses realm for Kerberos.

Go deeper

PCNSE Practice Question: Securing Users and Applications with Authentication

Exhibit

Why each option matters

Option-by-option breakdown

Related to this question