Interview Preparation

 Q: Can you describe your experience with Active Directory and how you have used it in your previous roles?

In my over 8 years of experience in IT infrastructure and systems administration, I've worked extensively with Active Directory (AD) across multiple roles, from on-premises deployments to hybrid environments integrated with Azure. It's been a cornerstone for managing user identities, security, and resource access in enterprise settings.

In my most recent role as a Senior Systems Administrator at [Company Name], I led the management of an AD environment supporting over 5,000 users in a multi-domain forest. I handled day-to-day tasks like user provisioning and deprovisioning using tools such as Active Directory Users and Computers (ADUC) and PowerShell scripting. For instance, I automated onboarding processes with scripts that created user accounts, assigned group memberships, and applied fine-grained password policies—reducing manual effort by 40% and minimizing errors.

Earlier, as an IT Support Engineer at [Previous Company], I focused on troubleshooting and security. I configured Group Policy Objects (GPOs) to enforce company-wide settings, like restricting USB devices and deploying software updates via WSUS integration. During a domain migration project following a company acquisition, I used the Active Directory Migration Tool (ADMT) to transfer users and groups seamlessly, ensuring zero downtime for critical services. I also monitored AD health with tools like DCDiag and Repadmin, identifying and resolving replication issues between domain controllers.

In a hybrid setup, I've synced on-premises AD with Azure AD (now Entra ID) using Azure AD Connect, enabling single sign-on for cloud apps like Microsoft 365. This was crucial in a project where we implemented conditional access policies to enhance security against potential breaches.

Overall, AD has taught me the importance of least-privilege access and regular audits—I've used Microsoft Defender for Identity to detect anomalies. I'm always eager to stay updated, recently exploring AD's role in zero-trust architectures. I'd love to bring this expertise to your team—how does AD fit into your current infrastructure?

Q: How do you approach troubleshooting issues with VPN connections and what tools do you use?

In my 10+ years in IT networking and security roles, I've troubleshooted countless VPN issues, from remote access setups in SMBs to enterprise-scale SD-WAN integrations. My approach is always systematic and layered, starting with the basics to rule out simple causes before diving into complex diagnostics. This minimizes downtime and ensures efficient resolution.

First, I verify the fundamentals: Is the user's internet stable? I check connectivity with basic commands like ping to a public site (e.g., ping google.com) and run speed tests to confirm bandwidth isn't the bottleneck. If it's intermittent, I might suggest restarting the router or switching networks. Next, I examine client-side issues—wrong credentials, outdated VPN software, or conflicting firewalls. For example, in my role as a Network Engineer at [Company Name], a user couldn't connect due to a misconfigured protocol; I guided them to check the VPN profile in Windows Network Connections and switch from UDP to TCP if ports were blocked.

If that's clear, I move to server-side or network-layer problems: Reviewing VPN server logs for authentication failures, ensuring required ports (like UDP 500/4500 for IPsec or TCP 443 for SSL VPNs) are open, and using traceroute to identify packet loss or routing issues. In one project, during a company-wide VPN rollout, we had disconnections from MTU mismatches; I used Wireshark to capture packets, analyzed fragmentation, and adjusted the MTU settings, resolving it for 200+ users with no further incidents.

Tools I rely on include:

• Built-in utilities: Ping, traceroute, and ipconfig/ifconfig for quick network diagnostics.
• VPN-specific: Client logs (e.g., from Cisco AnyConnect or OpenVPN) and server-side tools like Event Viewer on Windows Server or syslog on Linux-based VPNs.
• Advanced: Wireshark for packet sniffing, PingPlotter for visualizing latency over time, and monitoring platforms like Site24x7 for real-time alerts on VPN health.

I also emphasize documentation—logging steps in a ticketing system like Jira—and prevention, such as regular audits of VPN configs for security best practices. This approach reduced our average resolution time by 30% in my last role. What kinds of VPN technologies does your team primarily use here?"