A user is unable to log in to the domain with a desktop PC, but a laptop PC is working properly on the same network. A technician logs in lo the…

The combination of domain login failure and the inability to access a secure (HTTPS) website points directly to a system time issue. Active Directory domain authentication relies on the Kerberos protocol, which is time-sensitive. If a client PC's clock is skewed by more than five minutes (by default) from the domain controller's clock, authentication will fail. Similarly, SSL/TLS certificates used by secure websites have specific validity periods. If the PC's system time is outside this range, the browser will deem the certificate invalid and block access. The fact that a local login works confirms the OS is functional, isolating the problem to services dependent on correct time.

B. Dual in-line memory module failure: A RAM failure would likely cause more catastrophic symptoms, such as system crashes (BSODs), random reboots, or a failure to boot, not specific network authentication issues.

C. Application crash: This is a software-specific issue. A crashing application would not prevent a user from logging into the Windows domain, which is an operating system-level function.

D. Filesystem errors: While severe filesystem corruption could prevent the OS from loading properly, it does not specifically explain the dual symptoms of failed domain authentication and failed secure site access.

1. Microsoft Documentation: In the "Troubleshooting Kerberos authentication" guide

it states

"To work correctly

the system time on the client and the domain controller need to be within 5 minutes of each other... This is the default maximum time skew." This directly explains the domain login failure.

Source: Microsoft Learn

"Troubleshooting Kerberos authentication

" Section: "Time skew."

2. Microsoft Documentation: Regarding certificate validation

"If the Valid from date is in the future

or the Valid to date is in the past... the certificate is not valid." An incorrect system clock can place the current time outside this valid range

causing browsers to reject the connection to a secure site.

Source: Microsoft Learn

"Certificate validation

" Document ID: 892892b7-193c-424a-8a1c-12312d347a1d.

3. MIT OpenCourseWare: In course materials for "6.857 Computer and Network Security

" lectures on Kerberos emphasize its reliance on timestamps to prevent replay attacks. "Authenticator has client’s timestamp

encrypted with session key... Server checks if timestamp is recent enough." This highlights the fundamental requirement for synchronized clocks.

Source: MIT OpenCourseWare

6.857 Computer and Network Security

Fall 2014

Lecture 10: Authentication & Kerberos.