Avast Antivirus Firewall - Getting Started

Firewall monitors all network traffic between your PC and the outside world to protect you from unauthorized communication and intrusions. This feature is designed to require minimal input from you. To ensure you are protected, all you need to do is keep Firewall Turned on and, when prompted, select the appropriate Firewall profile for each network that you connect to. Firewall is a feature in Avast Premium Security and Avast Omni.

Enable or disable Firewall

To ensure your full security, Firewall is enabled by default. We recommend keeping Firewall enabled at all times, unless you need to disable it temporarily for troubleshooting purposes. To disable Firewall temporarily:

We do not recommend selecting the Stop indefinitely option to stop Firewall permanently.
  1. Open the Avast user interface.
  2. Click the Protection tile in the left menu, and select Firewall.
  3. Click the green (ON) slider, then select a time duration.
  4. Click OK in the dialog that appears.

Firewall is temporarily disabled. To enable Firewall, follow steps 1-2 above, then click the slider so that it changes from red (OFF) to green (ON).

Define Network profiles

This feature allows you to define network profiles based on the networks you're connected to, and monitor all communication between your PC and the web. On the main Firewall screen, every network your PC is connected to is shown under Current network. In the Firewall profile column, you can select the appropriate profile for each network. To manage Firewall network profiles:

  1. Open the Avast user interface.
  2. Click the Protection tile in the left menu, and select Firewall.
  3. Click the slider in the Firewall Profile column to select one of the following profiles for each network you're connected to:
    • Private: a lower level of security suitable for when your PC is connected to a trusted network, such as your home or work network. This profile enables better connectivity, and permits all communication within the network.
    • Public: a higher level of security suitable for when your PC is connected to a public network, such as in a cafe or airport. Because public networks present greater security risks, no incoming communication is permitted when this profile is selected.
    Every time you access a known network, Avast remembers and automatically applies the Firewall profile that you previously set. Although you can manage your network Firewall profiles on this screen, each time you connect to a new network, Avast prompts you to select the appropriate profile. Public is the default profile setting when no profile is selected.

Manage network connections

The Network connections screen displays a table of information regarding all recent incoming and outgoing communication with applications and processes running on your PC. To access Network connections:

To return to the main Firewall screen, click Close in the bottom-right corner of the Network Connections screen.

  1. Open the Avast user interface.
  2. Click the Protection tile in the left menu, and select Firewall.
  3. Click Network connections.
  4. From the Network Connections table, you can perform the following actions:
    • Tick the boxes above the table to alter the displayed information for each connection.
    • Right-click any connection to view its Application and Packet rules, or kill the connection completely.
    • Click a connection, then select File Details at the bottom of the table to learn more about the application, process, or connection you selected.

View Firewall logs

The Firewall Logs screen displays all records of Firewall activity history. You can configure the table to show specific activity, or search for a specific criteria in the table. To access the Firewall logs:

  1. Open the Avast user interface.
  2. Click the Protection tile in the left menu, and select Firewall.
  3. Click Firewall logs.
  4. Search the Firewall logs table with the following tools:
    • Next to Show log for, click the drop-down menu and select an activity type to view either Blocked traffic or Rules in the table.
    • Next to Show for last, define a time frame and time unit to see activities within a specific time period.
    • Tick the box next to Filter, then type your search into the relevant search fields that appear. Each search field corresponds directly to the column underneath it.
    • Next to Clear logs older than, define a time frame and time unit to delete selected log files.

Click Refresh to update the log using your defined criteria. To return to the main Firewall screen, click Close in the bottom-right corner of the Firewall logs.

Application Rules

Firewall creates rules each time an application or process starts for the first time. These rules determine how Firewall behaves toward each application or process when it connects to the internet or to another network. You can set connection allowances for each individual application to determine how strictly Firewall monitors any incoming or outgoing communication. However, we recommend you only modify your Application Rules if absolutely necessary. Usually Firewall can optimize rules without your input. To access Application Rules:

  1. Open the Avast user interface.
  2. Click the Protection tile in the left menu, and select Firewall.
  3. Select an app in the Apps recently managed by your Firewall section, or click Application settings.
  4. Manage the following options on the Application Rules screen:
    • Organize application rules by vendor name
    • Adjust access restrictions
    • Set actions for unathorized connections
    • Specify authorized ports
    • Access Packet rules

For more information about Application rules, refer to the following article:

We recommend only changing these settings if you have advanced knowledge of firewall concepts.

More Firewall settings

Advanced users can configure additional Firewall settings by going to MenuSettingsProtectionFirewall. The following settings are available:

  • Disable Firewall: click the green (ON) slider at the top of the Firewall settings screen, then select a time duration. We do not recommend the Stop indefinitely option.
  • Show notification about newly created 'allow' rules: tick the box next to this setting to receive notifications when allows or blocks a new communication path.
  • Internet Connection Sharing Mode: allows a trusted user to connect to the internet through your PC, or to troubleshoot problems with devices, such as a printer that is connected to the internet via your PC.
  • Enable automatic port scan detection: authorizes Firewall to detect port scan attempts.
  • For programs with no defined rules, do the following: use the drop-down menu to define what Firewall does when it detects a new communication path.
  • System Rules: click this button to configure individual pre-defined system rules.
  • Packet Rules: click this button to configure communication settings according to connection type.
  • List of network profiles: use the drop-down menu in an individual network panel to configure the network profile.
We recommend you only make alterations to System and Packet rules if you have advanced knowledge of firewall concepts. Firewall is already configured to provide the appropriate firewall protection in most cases.

Additional information

For more information about Firewall, refer to the following article:

  • Avast Premium Security 19.x
  • Avast Omni 1.x
  • Avast Premier 19.x
  • Avast Internet Security 19.x
  • Microsoft Windows 10 Home / Pro / Enterprise / Education - 32 / 64-bit
  • Microsoft Windows 8.1 / Pro / Enterprise - 32 / 64-bit
  • Microsoft Windows 8 / Pro / Enterprise - 32 / 64-bit
  • Microsoft Windows 7 Home Basic / Home Premium / Professional / Enterprise / Ultimate - Service Pack 1, 32 / 64-bit

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