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Managing Login Definitions

Learn how to manage system-wide login definitions, password aging policies, and default user account settings using the /etc/login.defs file.

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Overview

The /etc/login.defs file controls many of the default account creation and password policy settings used on Linux systems. In this lab, you will learn how to manage system-wide login definitions that affect user accounts, password aging, and user ID allocation. You will explore and modify settings related to password expiration, warning periods, minimum password age, and default UID/GID ranges. You will also verify how these settings affect newly created user accounts and generate a configuration report.

In This Lab, You’ll Learn How To

  • View and understand the login.defs configuration file
  • Manage default password aging policies
  • Configure password expiration and warning periods
  • Modify default UID and GID allocation ranges
  • Verify account settings for newly created users
  • Generate reports from login definition settings
  • Restore default login configuration values

Key Login Definition Settings

  • PASS_MAX_DAYS for maximum password age
  • PASS_MIN_DAYS for minimum password age
  • PASS_WARN_AGE for password expiration warnings
  • UID_MIN for the starting user ID range
  • GID_MIN for the starting group ID range
  • chage for verifying password aging policies

Command Examples

View the login definitions file:

cat /etc/login.defs

Check password aging settings:

grep '^PASS_MAX_DAYS' /etc/login.defs
grep '^PASS_MIN_DAYS' /etc/login.defs
grep '^PASS_WARN_AGE' /etc/login.defs

Check UID and GID ranges:

grep '^UID_MIN' /etc/login.defs
grep '^GID_MIN' /etc/login.defs

Verify password aging information for a user:

chage -l testuser1

Create a user to test default settings:

useradd testuser1

Learning Outcomes

  • Understand the role of /etc/login.defs in Linux
  • Configure system-wide password policies
  • Manage default account creation settings
  • Verify password aging and user allocation settings
  • Develop practical Linux administration skills

Conclusion

Completing this lab will help you gain practical experience managing login definitions and default account policies in Linux. You will learn how to configure password aging settings and account creation parameters that apply across the entire system. These skills are valuable for Linux system administration, LFCS preparation, and maintaining consistent security policies for user accounts.