Blog - Page 22 of 26 - InfoTech Ninja

Networking

Cisco IOS Access Control Lists: Standard, Extended, Named, Reflexive, Time-Based

Working reference for the five Cisco IOS ACL types. How an ACL processes a packet (top-down, first-match-wins, implicit deny), where the order of operations relative to NAT matters (in: ACL before NAT, out: NAT before ACL), Standard vs Extended vs Named ACLs with full configuration examples, Reflexive ACLs for basic return-traffic state, Time-based ACLs with absolute and periodic schedules, application to interfaces vs VTY lines (ip access-group vs access-class), placement rules (Standard close to destination, Extended close to source), and the pitfalls (implicit deny, numbered-ACL edit gotcha, wildcard vs subnet mask, NAT-order trap, missing VTY restriction).

Networking

Configure OSPFv2 on Cisco IOS: From Single Area to Multi-Area

Working reference for OSPFv2 on Cisco IOS - the cost metric, hello/dead timers, the six LSA types, the five area types (Backbone, Normal, Stub, TSA, NSSA), router roles (ABR, ASBR, IR), basic configuration with both the network statement and ip ospf interface command, multi-area design, summarization at the ABR (area range vs summary-address), virtual links, MD5 authentication, the five verification commands, and the pitfalls (reference bandwidth mismatch, wildcard vs subnet mask, EXSTART MTU loops, implicit router-id changes).

Systems Admin

Check Active Directory Forest and Domain Functional Level

How to read the current Active Directory forest functional level (FFL) and domain functional level (DFL), what each level unlocks, the pre-flight checklist before raising, and how to actually raise it with Set-ADForestMode / Set-ADDomainMode. Includes the schema-version-to-OS table, a decision flow for whether to raise, and the common pitfalls (forgotten DCs, Server 2019/2022 reporting Windows2016Forest, irreversibility).

Systems Admin

Export Active Directory Users to CSV with PowerShell

Export AD users to CSV using the three-cmdlet pipeline (Get-ADUser, Select-Object, Export-Csv). Covers scope selection (-Filter, -SearchBase, -SearchScope), the computed-property pattern for columns like Manager-DN-to-name and clean OU paths, a reusable function with parameters, and common variations (disabled accounts, stale logons, group membership exports).

Systems Admin

How to Install Windows Updates with PowerShell

Drive Windows Update from a single PowerShell window using the PSWindowsUpdate module. Covers installing the module from the PowerShell Gallery, querying and installing updates on local and remote machines, looping over a hard-coded computer list, and patching every member of an Active Directory OU dynamically with Get-ADComputer -SearchBase.

Systems Admin

Get Active Directory Information with a PowerShell Script

Get-ADInfo.ps1 is a single PowerShell script that prints ten Active Directory facts in one output: computer/workstation/server/user/group counts, forest and domain functional levels, schema version translated to a Windows Server release name, and all five FSMO role owners. The right script to run before a migration, an audit, or a tier-zero handover.

Systems Admin

Create Active Directory Users from CSV with PowerShell

Bulk-create AD users from a CSV in seconds instead of clicking the ADUC wizard for hours. Covers designing the CSV template, generating strong passwords, finding the target OU's distinguishedName, importing the file with Import-Csv, and the Add-NewUsers.ps1 script that splats parameters into New-ADUser with a duplicate check and try/catch error handling.

Systems Admin

Secure Active Directory Passwords from Breaches

Audit and harden Active Directory against breached passwords using Lithnet Password Protection and the Have I Been Pwned compromised hash list. Covers installing Lithnet PP on a Domain Controller, syncing the HIBP store, running the Audit-Passwords.ps1 script to find pwned accounts, and configuring the GPO that rejects new pwned passwords on every set/change.

Systems Admin

Back Up and Restore the Windows Registry

Step-by-step guide to backing up and restoring the Windows registry: open Registry Editor, choose File > Export, pick All or a single branch, save the .reg file, and restore later via File > Import or by right-clicking the .reg file and choosing Merge - including the Safe Mode workflow when Windows will not boot.

Systems Admin

How to Check FSMO Roles in Active Directory

Three reliable ways to check FSMO role holders in Active Directory: the netdom query FSMO command, the Get-ADForest/Get-ADDomain PowerShell cmdlets (and the Get-ADInfo.ps1 script), and the GUI walkthrough across Active Directory Schema, Active Directory Domains and Trusts, and Active Directory Users and Computers.

Systems Admin

Fix the Not Digitally Signed Error When Running a PowerShell Script

Why downloaded PowerShell scripts trigger a 'not digitally signed' error and how to fix it. Covers the Mark of the Web (Zone.Identifier) NTFS alternate data stream, three fix options (GUI Unblock, Unblock-File cmdlet, -ExecutionPolicy Bypass), and the execution policy values you should and should not use.

Systems Admin

Enable the Active Directory Recycle Bin

Step-by-step guide to enabling the Active Directory Recycle Bin forest-wide using Active Directory Administrative Center. Covers prerequisites, the irreversible nature of the change, GUI and PowerShell verification, restoring deleted objects with Restore-ADObject, and follow-up hardening like Protect from accidental deletion.

The Dojo