DomainBlock

Windows PowerShell toolkit for blocking and inspecting domains via the hosts file and Windows Firewall.

Requires Windows PowerShell 5.1 or PowerShell 7 on Windows. Changing the system hosts file or firewall rules needs an elevated session.

Import-Module .\DomainBlock

Invoke-DomainBlockWorkflow -Action Apply -Name ads.example.com -Method Hosts
Get-BlockedDomain
Invoke-DomainBlockWorkflow -Action Remove -Name ads.example.com -Method Hosts

Hosts entries look like:

127.0.0.1 ads.example.com # DomainBlock
::1 ads.example.com # DomainBlock

Firewall rules are named per domain and IP, grouped as DomainBlock. Re-running Block-Domain does not create duplicates.

Firewall IP blocks go stale when CDNs rotate addresses. Refresh them with Update-DomainFirewallBlock. Hosts-file blocks can be bypassed by DNS-over-HTTPS, VPNs, or apps that ignore the system resolver.

Commands

Command	Purpose
Block-Domain	Block via hosts, firewall, or both
Unblock-Domain	Remove toolkit-managed blocks
Get-BlockedDomain	List what this module created
Test-DomainBlock	Hosts + firewall + loopback DNS view
Update-DomainFirewallBlock	Re-resolve DNS and sync firewall IPs
Find-FirewallDomainRule	Search any firewall rule covering a domain's IPs
Get-DomainIPAddress	Resolve A/AAAA addresses
ConvertTo-DomainListLiteral	Column of names → @("a", "b")
Backup-HostsFile / Restore-HostsFile	Timestamped hosts backups under Documents\DomainBlock
Export-BlockedDomain / Import-BlockedDomain	Text or JSON domain lists
Invoke-DomainBlockWorkflow	Run Apply, Refresh, or Remove as a sequence

Get-Help about_DomainBlock
Get-Command -Module DomainBlock
Get-Help Block-Domain -Examples

Sequences

Running every command in order is not useful: Block-Domain and Unblock-Domain cancel each other, and Restore-HostsFile undoes a backup.

The sequences that are worth chaining, each step waiting for the previous to finish:

Action	Steps
Apply	Backup-HostsFile → Block-Domain → Test-DomainBlock
Refresh	Update-DomainFirewallBlock → Test-DomainBlock
Remove	Backup-HostsFile → Unblock-Domain → Test-DomainBlock

Invoke-DomainBlockWorkflow -Action Apply -Path .\examples\DomainList.txt -Method Hosts
Invoke-DomainBlockWorkflow -Action Refresh
Invoke-DomainBlockWorkflow -Action Remove -Name ads.example.com

Use the individual commands when you need a single step (Get-BlockedDomain, Find-FirewallDomainRule, export/import, restore).

Lists

examples/DomainList.txt is a commented template. One domain per line; # comments are ignored. JSON from Export-BlockedDomain is also accepted.

Block-Domain -Path .\examples\DomainList.txt -Method Hosts -WhatIf
Get-Content .\list.txt | ConvertTo-DomainListLiteral

Tests

pwsh -NoProfile -ExecutionPolicy Bypass -File .\tests\Invoke-DomainBlockTest.ps1

Hosts-file tests use a temp file and do not require elevation. Firewall live tests are skipped unless you pass -LiveFirewall in an elevated session.

License

MIT. See LICENSE.