GeoWF

⚠️ Disclaimer: Don't ever expose RDP (or anything like it) directly to the internet. It was simpler times when I first wrote this.

GeoWF (GeoIP Windows Firewall) is a PowerShell script which can modify accepted remote address ranges on inbound Windows Firewall rules using MaxMind's GeoIP (GeoLite2) databases, allowing Windows Firewall to function as a poor man's firewall with geoblocking.

Demonstration

This demo is running with -InformationAction Continue in order to show more verbose output.

Usage

⚠️ Windows Firewall has a limitation of 10,000 remote IP ranges per rule.

PowerShell must be running elevated to make changes to Windows Firewall.

On your first run, you'll need to sign up for a free MaxMind account and set your license key:

.\GeoWF.ps1 -MaxMindLicenseKey abcdefgh12345678

You can list all countries and their corresponding two letter ISO country codes:

.\GeoWF.ps1 -ListCountries

By default, local subnet is included on firewall rules. This can be turned off by specifying the -ExcludeLocalSubnet switch.

Example 1

Limit all rules in the Remote Desktop group to Australia and New Zealand:

.\GeoWF.ps1 -RuleDisplayGroup "Remote Desktop" -Country AU,NZ

Example 2

The following command could be used as a scheduled task to periodically update GeoIP databases and limit VNC Server and ping replies to Sweden:

.\GeoWF.ps1 -ForceDownload -RuleDisplayName "VNC Server","File and Printer Sharing (Echo Request - ICMPv4-In)" -Country SE

Caveats

• Windows Firewall limits IP ranges to 10,000 per rule. I wish I knew this before creating this script. I may add a workaround (such as splitting rules) in the future.
• -RuleName is not to be confused with -RuleDisplayName. The former is either a shorthand name or GUID and the latter is how rule names appear in wf.msc.
• Multiple rules can share the same display name.