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Frequently Asked Questions

Here are the most common problems running PowerShell scripts from this repository and how to resolve them.
In addition, general questions and answers regarding this firewall.

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Firewall rule doesn't work, program "some-program.exe" fails to connect to internet

First step is to open PowerShell as Administrator and run gpupdate.exe, if not working then:

  1. Close down the program which is unable to connect to network completely, including system tray.
  2. In GPO firewall SHIFT select each rule that applies to this program, right click and disable, wait two seconds then enable again.
  3. Open program in question and try again, in most cases this should work.
  4. If not try rebooting system, Windows firewall sometimes just doesn't instantly respect rules.
  5. If still no luck, open rule properties in GPO and under Advanced tab allow all interface types and allow all users under Local Principals tab, however allowing all interfaces or users should be only a temporary measure for troubleshooting.

NOTE: In addition to interfaces shown in GPO there are some hidden network interfaces, until I figure out how to make rules based on those allow them all to rule out problem with interfaces.
To troubleshoot hidden adapters see Problematic Traffic

If steps above do no solve the problem, reload rules which do not work, sometimes system or program changes make existing GPO rules ineffective.

Other than this, if problem persists, you'll have to debug the problem, to get started see MonitoringFirewall.md

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I get an error "Network path not found", "Unable to contact computer" or "The client cannot connect"

First verify the following network adapter items are enabled (checked) and if not restart adapter for any changes to take effect:

  1. Client for Microsoft Networks
  2. File and Printer Sharing for Microsoft Networks
  3. Internet Protocol version 4 (TCP/IPv4)
  4. Internet Protocol version 6 (TCP/IPv6)
  5. Link-Layer Topology Discovery Responder
  6. Link-Layer Topology Discovery I/O Driver

For more information about these items and how to manage them see AdapterItems.md

Next ensure at the minimum the following network services are Running and optionally set to Automatic startup

  1. LanmanWorkstation: Workstation
  2. LanmanServer: Server
  3. lmhosts: TCP/IP NetBIOS Helper service
  4. WinRM: Windows Remote Management (WS-Management)
  5. RemoteRegistry Remote Registry
  6. FDResPub Function Discovery Resource Publication
  7. fdPHost Function Discovery Provider host

Next ensure that on computer which you're trying to access the following is enabled for private network profile:

  1. Turn on network discovery
  2. Turn on file and printer sharing

This can be enabled in the following location:
Start->System->Network & Internet->Network and Sharing Center->Change advanced sharing settings

If this doesn't work verify the command that is causing this problem, for example the following command tries to get firewall rules from GPO and will produce this problem:

Get-NetFirewallRule -PolicyStore [System.Environment]::MachineName

In this example to fix the problem modify command above to the following and it should work:

Get-NetFirewallRule -PolicyStore ([System.Environment]::MachineName)

If you're trying to deploy or manage firewall remotely see this document Remote.md

If none of this works even after reboot of all involved computers, the following link might help:

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Does this firewall project give me the right protection

Good firewall setup is essential for computer security, and if not misused then the answer is yes but only for the firewall part of protection.

Keep in mind that this project is still alpha software, not yet ready for production use, see What's alpha software

For maximum security you'll need much more than just good firewall, for start you can read trough SecurityAndPrivacy.md

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Windows Firewall does not write logs

This could happen if you change default log file location in Windows Firewall settings

To resolve this issue ensure the following:

  1. Verify current logging setting is enabled and is pointing to expected log file location.

    To verify this, open firewall properties in GPO and select current network profile tab:

    • Under logging section click on Customize... button
    • Under Name verify location to log file is correct
    • Under Log dropped packet make sure it's set to Yes

  2. Ensure that log files were generated in the specified location.

    • If log files were not generated go to step 3 below to grant permission to specified directory and then get back here to step 2
    • If you applied write permission to specified directory and log files aren't generated temporarily toggle setting to log successful connections and apply it, this should force generating logs.

  3. Verify that both the target directory and all the logs inside that directory grant write
    permission for Windows Firewall service which is NT SERVICE\mpssvc

  4. For changes to take effect save your modifications and restart firewall or reboot system.

Keep in mind that setting additional permissions afterwards will be reset by Windows firewall service on every system boot or firewall setting change for security reasons.
If this doesn't resolve the problem remove all log files inside target directory, to be able to do this, you'll have to instruct firewall to write to different location to set your logs free, then reboot system.

Also keep in mind that firewall service can't be stopped or manipulated in any way except trough UI followed by reboot.

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Can I trust scripts from this repository

  • You might be wondering, what happens to my system if I run scripts from this repository?
  • Can these scripts do any kind of harm to my computer or privacy?
  • What system and environment modifications are done to setup firewall?
  • Is there anything else I should be aware of?

There is a lot of scripts and you might not have the time to investigate them all.
So here is an overview to help you see what they do hopefully answering all of your concerns.

  1. Group policy firewall and all of it's settings are modifed and/or overridden completely.

    • If you make modifications to GPO firewall, rerunning scripts again may override your modifications.

  2. Some global firewall settings are modified as explained here Set-NetFirewallSetting

    • For details on which settings are modified see Scripts\Complete-Firewall.ps1

  3. PowerShell module path is updated for current session only

    • Running any script will add modules from this repository to module path for current PS session only.
    • Once you close down (or open new) PowerShell session, module path modifications are undone.

  4. Required system services are started and set to automatic startup

    • Inside Logs you'll find Services-<DATE>.log to help you restore defaults

  5. WS-Management service (Windows Remote Management) configuration is modified

    • WinRM configuration is completely modified

    • PowerShell remoting may be enabled either for loopback or remote sessions which does the following:

      • Starts the WinRM service.
      • Sets the startup type on the WinRM service to Automatic.
      • Creates a listener to accept requests on loopback IP address.
      • Temporarily enables firewall exception for WS-Management communications.
      • Creates the simple and long name session endpoint configurations if needed.
      • Enables all session configurations.
      • Optionally changes the security descriptor of all session configurations to allow remote access.

    • Default PowerShell session configurations are recreated and optionally disabled

    • Custom session configurations are created which is used for local and remote firewall deployment

    • Your own PowerShell session configurations if you made them will be removed

  6. The following default firewall rules are recreated or removed in control panel firewall

    • Rules for Network Discovery, File and Printer Sharing, WinRM and WinRM compatibility rules

  7. All other system or session settings are left alone by default unless you demand or accept them as follows:

    • Adjust console buffer size (valid until you close down PowerShell)
    • Update PowerShell module help files (only if you enable development mode)
    • Install or update dependent PowerShell modules (only if you enable development mode or if you set ModulesCheck variable to $true manually)
    • Install recommended VSCode extensions (if you accpet VSCode recommendation)
    • Modify file system permissions (ex. after setting firewall to log into this repository)
    • Modify settings for specific software (Process monitor, mTail and Windows Performance Analyzer only)

    All of modifications above are done in the following situations:

    • VScode might ask you to install recommended extensions
    • Some script might ask you to confirm whether you want to do this or that, and you're free to deny by default.
    • You have enabled "development mode" project setting
    • You run some script on demand that is not run by default (ex. Set-Permission.ps1)
    • You manually load software configuration from Config directory
    • You run experimental or dangerous tests from Test directory (default action for these tests is No)

  8. Here is a list of scripts that may behave unexpectedly or do things which are potentially not desired because these are either experimental, not intended for end user or hard to get right, therefore you might want to review them first to learn their purpose:

    • Scripts\Grant-Logs.ps1
    • Scripts\Set-ATP.ps1
    • Scripts\Set-Privacy.ps1
    • ...\Ruleset.Utility\Set-Privilege.ps1
    • ...\Ruleset.Utility\Set-Permission.ps1
    • ...\Ruleset.Initialize\Initialize-Module.ps1
    • ...\Ruleset.Initialize\Initialize-Provider.ps1
    • ...\Ruleset.Initialize\Uninstall-DuplicateModule.ps1
    • ...\Ruleset.Remote\*.ps1

    By default none of these scripts (except scripts in Ruleset.Remote) run on their own, except as explained in point 5.
    Those scripts listed above which begin with ...\ exist in Modules and Test subdirectories.

  9. The following is a list of external executables that are run by some scripts

  10. There is nothing harmful to privacy or system security

    • Some scripts such as initialize-module.ps1 will contact online PowerShell repository to download or update modules, however this happens only if you manually enable setting
    • Some scripts are potentially dangerous due to their experimental state such as Uninstall-DuplicateModule.ps1 which may fail and leave you with broken modules which you would have to to fix with your own intervention.
    • "development mode" may be enabled by default on develop branch but never on master branch, which means defaults described so far may no longer be defaults
    • Scripts will gather all sorts of system information but only as required to configure firewall, none of this information is ever sent anywhere and once you close down PowerShell it's all cleared.
    • If you publish your code modifications online (ex. to your fork) make sure your modifications don't include any personal information such as user names, email or system details.
    • Bugs may exist which could break things, while I do my best to avoid bugs you might want to report your findings to be fixed.
    • If you believe there is security or privacy issue please see Security.md

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Why do I get "Access is denied" errors

There are several possible causes as follows:

  • If your Administrator account is using Microsoft account to log into computer you need to specify microsoft email and password.
    If you're using PIN and if you recently changed your Microsoft email password this may cause your credentials to not work for which the solution is to remove your PIN and then setting PIN again.

  • You might also see this error while loading firewall rules.

    In almost all cases this happens when you use one of the management consoles such as gpedit.msc or secpol.msc, especially if you do something with them (ex. refreshing group policy, viewing or modifying settings/rules)

    To minimize the chance of this error from appearing close down all management consoles and all software that is not essential to deploy firewall and try again.

  • The "Access is denied" error may also be reported by WinRM or CIM, see Remote.md to resolve these kinds of "Access is denied".

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I'm missing network profile settings in Settings App

In Settings -> Network & Internet -> Status -> Properties there should be options to set private or public profile for your adapter, but what if these options are gone and how to get them back?

These profile settings go missing when sharing your physical NIC with virtual switch with virtual machine.
If you have configured external switch in your Hyper-V there is nothing you can do to except to stop sharing your hardware NIC with virtual switch.

There are many options to troubleshoot this problem, most of which are just a workaround but don't actually bring these options back, so here are my favorites that should fix it instead:

  1. First open up Control Panel firewall and see if there is a message that says:
    For your security, some setting are controlled by Group Policy

  2. If you can't get rid of the message and profile options are not back even after reboot, next step is to verify the following location in GPO:
    Computer Configuration\Windows Settings\Security Settings\Network List Manager Policies

    Here make sure everything is set to Not Configured, and if you change something reboot system to verify.

  3. If profile options are still not back there is only one option left which is resetting network settings as follows:

    • Settings -> Network & Internet -> Network Reset
    • Make sure not to reboot until required time has passed, usually 5 minutes, let it reboot on it's own and profile options should re-appear.

The maximum number of concurrent operations for this user has been exceeded

This error may happen when using PS Core to deploy firewall because in PS Core up to 3 sessions may be created during initial configuration while using single PS Core console.
This means if second console is opened it will exceed the default value of 5 sessions.

There are few solutions:

  1. Close down all PS Core consoles (including ghost windows), wait some time and try again with single PS Core console.

  2. You can increase the limit in Modules\Ruleset.Remote\Scripts\WinRMSettings.ps1, here search for MaxShellsPerUser and increase the value to 10, 20 or more, the default value is 5.

  3. If nothing works the easiest workaround is either reboot system or use Windows PowerShell for the time being.

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Why do I need to specify my Microsoft account credentials

If you're using Microsoft account to log in to your computer you will be asked for credentials, which needs to be your Microsoft email and password used to log into computer regardless if you're using Windows hello or not, specifying PIN ie. will not work and other Windows hello authentication methods are not supported.

If invalid credentials are supplied you'll get an error saying Access is denied.
If this happens you'll need to restart PowerShell console and try again.\

If you're using PIN and if you recently changed your Microsoft email password this may cause your credentials to not work for which the solution is to remove your PIN and then setting PIN again.

The reason why this is necessary is because this firewall uses PowerShell remoting and WinRM service to deploy rules, by default PS Remoting will use your NTLM username\password, however this method does not work if Microsoft account is used because NTLM username is not the same as Microsoft account username, which results in an error saying that such user does not exist.

Thus the only way for proper authentication is to ask user for valid Microsoft account credentials, which needs to be of an Administrative account on computer.
The credentials are securely stored in an object of type PSCredential and once you close down PowerShell the credential object is destroyed.

Windows hello is neither supported nor necessary by PowerShell remoting or WinRM.

Network icon in taskbar says "No Network"

You might stumble upon the following icon in your taskbar:

Alternate text

Internet might or might not work but the icon says "No Network".

If your internet connections works this problem happens either due to something with DHCP or DNS:

  • If you're using DHCP to resolve this problem run:
ipconfig /release
Clear-DnsClientCache
ipconfig /renew

And then disable and re-enable your network adapter.

  • If you use custom DNS software such as dnscrypt-proxy which modifies DNS entry of a NIC you'll need to add alternate DNS server that is not using DNS encryption to the NIC.

  • If you're sharing your NIC with virtual switch in VM (ex. Hyper-V), you might need to release physical NIC in Hyper-V and re-share it again.

  • If you use VPN it might have to be re-applied or reconfigured as well.

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PowerShell Core throws a black console window

When using PowerShell Core a blank black windows is created, this is known issue which has not yet been resolved, you can track the issue here: New-PSSession throws a black window

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Duplicate log entries

Duplicate log entries appear if a script is dotsourced, it should be called rather than dotsourced.
If scripts are run with PS debugger or with Run -> Run Without Debugging duplicate log entries will appear because script will get dotsourced.
See also this issue Configuration option to debug or run a script without dot sourcing it

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For your security, some setting are controlled by Group Policy

This message is present in control panel firewall when at least one option in GPO firewall is modified or when at least one rule exists in GPO firewall.
To get rid of this message GPO firewall needs to be cleared to system defaults.

  • First step is to reset GPO firewall to defaults by using Scripts\Reset-Firewall.ps1, but don't do anything to firewall in Control Panel.
  • When done reboot system and see if this message has gone and also whether profile options are back.
  • If the message is still there, you can try to recall any security policies you did in GPO, it doesn't have to be related to firewall, ex. anti virus, network options or anything similar can be the cause for this message.
  • If nothing helps, in GPO firewall right click on node: Windows Defender Firewall with Advanced Security - Local Group Policy Object and select Clear Policy

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Where are firewall rules stored in the registry

Control panel firewal rules (which include rules from GPO) are stored in:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\FirewallRules

GPO rules are stored in:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\FirewallRules

Default rules are stored in:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Defaults\FirewallPolicy\FirewallRules

WFP binary blobs are stored in:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\BFE\Parameters\Policy\Persistent\Filter

When you start the group policy editor and edit a local policy, the settings are loaded by the editor in the following location (which includes a bunch of firewall rule entries):

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Group Policy Objects

If the group policy editor ends, the key "Group Policy Objects" deleted again. From time to time it can happen that the entries are retained (if the group policy editor crashes or the keys could not be deleted). You can then delete these keys yourself, otherwise these keys will remain as registry corpses, since the group policy editor will start the entries under a new one next time UID will leave there.

Source

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