Gary VirkIT Specialist

Work Executed labs · cited support notes

Selected IT support and networking work.

Each lab starts with a fault, shows the evidence used to isolate it, and ends with a retest. Technical notes are based on cited vendor guidance and are not presented as executed work.

Employer records are not published. Generated images are labelled and used only for explanation.

Captured output
Collected during a controlled lab.
Derived view
Built from captured lab data.
Technical note
Based on cited vendor guidance.
Editorial image
Used for explanation, never proof.
Packet Tracer browser showing the inserted HTTPS timeoutFault
Packet Tracer router output showing the inserted ACL deny and match counterDecisive check
Packet Tracer browser showing HTTPS restored after the ACL correctionRetest
View the ACL case study

01

Detailed case studies

Troubleshooting and change records with selected public evidence.

01

IT support · PowerShell · Windows 11

Windows endpoint connectivity triage

A PowerShell diagnostic that distinguishes a DNS failure from a wider connectivity problem, then records the result for handoff.
What it shows

Direct TCP still works while name resolution fails, narrowing the fault to DNS.

Controlled Windows 11 ARM64 run

02

Networking · Cisco ACLs · Batfish

Validating a network access rule change

This lab tests one ACL change against required and blocked traffic, corrects a deliberate regression, and repeats the baseline checks.
What it shows

Removing the inserted deny restores user HTTPS while guest-to-admin traffic remains blocked.

Batfish model and Packet Tracer checks

02

Supporting labs

Shorter endpoint, systems, and network records with clear limits.

03

IT support · DHCP · Packet evidence

DHCP failure isolation

A controlled DHCP run separates a missing offer, incorrect lease options, and two servers answering the same transaction.
What it shows

The packet sequence separates no response, incorrect lease options, and two responding servers.

Isolated ARM64 Linux packet lab

04

Networking · TShark · Troubleshooting

Four packet captures, four network faults

Four short cases cover DNS failure, a TCP reset, duplicate-IP ARP, and path MTU, each with a post-change capture.
What it shows

Each note identifies the frames that explain the symptom and keeps the post-change capture separate.

Isolated ARM64 packet lab

05

Networking · Nmap · Inventory comparison

Network inventory drift

In an isolated Docker network, an Nmap comparison identifies one missing device, one new device, one address change, and one uncertain observation.
What it shows

The report separates confirmed changes from one uncertain observation, then returns zero findings after correction.

Isolated Docker and Nmap run

06

Systems support · TLS · OpenSSL

TLS certificate and hostname triage

A loopback service test separates an untrusted issuer from a hostname mismatch, then verifies the corrected certificate and HTTPS response.
What it shows

A reachable port is not enough. The client must trust the issuer and the requested hostname must match the certificate.

Local OpenSSL service run

07

IT support · SMB · Samba

SMB authentication and share permissions

An isolated Samba lab shows the difference between a wrong password and a valid user who lacks access to the share.
What it shows

Two users can reach the same SMB service and fail for different reasons, so connectivity, authentication, and authorization must be checked separately.

Isolated Samba client and server run

08

Systems support · HTTP · Nginx

Tracing an HTTP 502 through a reverse proxy

The proxy is reachable and the backend is healthy. The error log points to one incorrect upstream port.
What it shows

A client-facing 502 does not prove the application is down. Direct upstream health and proxy configuration must be checked separately.

Isolated proxy and backend run

09

Systems support · SSH · Linux

SSH access and private-key permissions

The SSH service is reachable, but access fails first with the wrong key and then because the correct key has an unsafe local file mode.
What it shows

A reachable SSH port does not prove that the client can use its key or that the server accepts the requested account.

Isolated OpenSSH client and server run

10

IT support · Application deployment · POSIX shell

Endpoint application deployment and rollback

A deliberately faulty release passes its package checks, fails its health test, rolls back to the last working version, and is replaced by a corrected release.
What it shows

A package can pass its file checks and still leave the application unusable. The lab verifies the active version, application health, rollback, and two named data files separately.

Local disposable-endpoint run

03

Support notes

Source-cited troubleshooting paths. These are not executed labs.

N1

Technical note · macOS · Intune · FileVault

macOS enrollment and FileVault support guide

This guide helps locate where a Mac stopped: enrollment, policy delivery, FileVault, or recovery-key handling.
Decision

The next action depends on where the enrollment or encryption path stopped and whether device-owner or administrator approval is required.

Vendor sources and labelled aids

N2

Technical note · Hardware · Windows recovery

Laptop boot and storage troubleshooting guide

This checklist helps decide whether a no-boot laptop needs hardware service, BitLocker recovery, or Windows repair.
Decision

The startup stop point determines whether to preserve evidence, obtain an approved recovery key, begin Windows recovery, or hand the device to hardware service.

Vendor sources and labelled aids

N3

Technical note · Wi-Fi · 802.1X · Windows

Enterprise Wi-Fi troubleshooting guide

The Windows checklist moves from adapter and association through 802.1X, DHCP, gateway, DNS, and service reachability.
Decision

A useful handoff identifies the failed layer and preserves the client evidence for the next owner.

Vendor sources and labelled aids