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CompTIA Exam XK0-005 Topic 4 Question 54 Discussion
Topic #: 4
A developer is unable to access a Linux server via SSH. Given the following output:
SSH server configuration (/etc/ssh/sshd_config):
PermitRootLogin no
PubkeyAuthentication yes
PasswordAuthentication yes
GSSAPIAuthentication yes
X11Forwarding no
User Information (/etc/passwd):
developer:x:1000:1000:comptia:/home/developer:/bin/bash
User Shadow File (/etc/shadow):
developer:!!::0:99999:7:::
Which of the following explains why the developer is unable to log in to the server?
The reason the developer cannot log in is because their account is locked. This is indicated by the '!!' in the /etc/shadow file:
developer:!!::0:99999:7:::
The '!!' in the password field means the account is locked, and the user cannot authenticate using a password.
To unlock the account, the administrator must reset the password:
passwd developer
OR, if SSH key authentication is used, the administrator can remove the lock without setting a password:
usermod -U developer
Why the other options are incorrect?
A . The developer's private key has been deleted from the server. Incorrect, because the login attempt is failing before key authentication even starts.
C . The developer's public key is in the wrong location. Incorrect, because the SSH configuration (PubkeyAuthentication yes) allows key-based authentication, but the user is still unable to log in. The issue is with the account lock.
D . SSH has been disabled for user log-in. Incorrect, because PasswordAuthentication yes confirms SSH is enabled for users (except root).
CompTIA Linux+ Official Documentation
Linux User Management -- Red Hat
Portia
3 days ago