Analysis of Windows 7 system firewall configuration

Windows xp integrated firewall is often seen as a chicken, but now the powerful features of Win7 firewall also have a "professional" taste. Today, I will teach you how to use the Win7 firewall.

The same as Vista, you can configure the Windows 7 firewall by accessing the control panel program. Unlike Vista, you can also perform advanced configuration (including configuration of outbound connection filters) by accessing the control panel instead of having to create a blank MMC and join the embedded snap-in. Just click on the advanced configuration option in the left panel.

Vista firewall allows you to choose whether to be on a public grid or a private network, and in Windows 7, you have three choices - public, home, and office. The latter two options are the refinement of the private network.

If you choose the "Home Network" option, you will be able to create a "family group." In this environment, “Network Discovery” will start automatically, you will be able to see other computers and devices on the network, and they will also be able to see your computer. Computers belonging to the "family group" can share pictures, music, videos, document libraries, and hardware devices such as printers. If you have folders that you don't want to share in the document library, you can also exclude them.

If you choose "Work Network", "Network Discovery" will also start automatically, but you will not be able to create or join the "Family Group". If your computer joins the Windows domain (via Control Panel - System and Security - System - Advanced System Configuration - Computer Name tab) and passes DC authentication, the firewall will automatically recognize the network type as the domain environment network.

The "public network" type is the appropriate choice when you are connected to a public Wi-Fi network at an airport, hotel, cafe or mobile broadband network. "Network Discovery" will be turned off by default, so other networks The computer in the middle will not discover your share and you will not be able to create or join the "family group".

In all network modes, Windows 7 Firewall will block any connection sent to applications that are not whitelisted by default. Windows 7 allows you to configure different network types separately.

Multiple-Action Firewall Policy

In Vista, although you have two profiles for public and private networks, only one will work for a specified amount of time. So if your computer happens to connect two different networks at the same time, then you have to be unlucky. The most restrictive profile will be taken by the user to all connections, which means you may not be able to do what you want on the local (private) network because you are operating under the rules on the public network. In Windows 7 (and Server 2008 R2), different profiles can be used on different network adapters. That is to say, the network connection between the private networks is governed by the private network rules, and the traffic between the public networks applies the public network rules.

There are small things that are not conspicuous.

In many cases, better usability often depends on small changes, MS listens to users and puts some "inconspicuous" Also played a small thing" joined the Windows 7 firewall. For example, when you create a firewall rule in Vista, you must list each ip address and port separately. Now you only need to specify a range, so the time spent on performing general management tasks is greatly reduced.

You can also create Connection Security Rules in the firewall console to specify which ports or protocols have the need to use IPsec without having to use the netsh command. For those who like the GUI, this is A more convenient improvement.

Connection Security Rules also supports dynamic encryption. This means that if the server receives an unencrypted (but verified) message from the guest, the security association will request encryption through the agreed "running" to establish a more secure communication.

Configure the configuration file in "Advanced Settings"

Using the "Advanced Settings" control panel, you can set the configuration file for each network type.

For configuration files, you can make the following settings:

* Turn on/off the firewall

* (Block, block all connections or allow) Inbound connections

* (Allow Or intercept) Outbound connection

* (Notify you when a program is blocked) Notification display

* Allow unicast to respond to multicast or broadcast

* Allowing local administrators to create and apply local firewall rules in addition to Group Policy firewall rules

About configuring system firewalls with netsh.exe

(1). View, enable or disable system firewalls

Open a command prompt and enter the input command “netsh firewallshow state” and press Enter to check the status of the firewall. From the displayed results, you can see the disable and enable of each function module of the firewall. The command "netsh firewall set opmode disable" is used to disable the system firewall. The command "netsh firewall set opmode enable" is used to enable the firewall.

(2). Allow file and print sharing

File and print sharing are commonly used in LAN. If you want to allow clients to access shared files or printers of this machine, you can input and execute them separately. The following command:

netsh firewall add portopening UDP 137 NetbiOS-ns

(allows the client to access the server UDP port 137)

netsh firewall add portopening UDP 138 NetbiOS- Dgm

(Allow access to port 138 of UDP protocol)

netsh firewall add portopening TCP 139 NetbiOS-ssn

(Allow access to TCP port 139)

netsh firewall add portopening TCP 445 NetbiOS-ds

(Allow access to TCP port 445)

After the command is executed, the ports required for file and print sharing are released by the firewall. .

(3). Allow ICMP echo

By default, Windows 7 does not allow external hosts to ping it for security reasons. However, in a secure LAN environment, the Ping test is necessary for the administrator to perform network testing. How to allow the Windows 7 ping test to be echoed?

Of course, through the system firewall console, you can enter In the Station Rules, set the File and Print Sharing (Echo Request - ICMPv4-In) rule to Allow (if the network uses IPv6, the rules for ICMPv6-In are also allowed.). However, we can quickly implement the netsh command from the command line. Run the netsh firewall set icmpsetting 8 command to enable ICMP echo. Otherwise, run netsh firewall set icmpsetting 8 disable to disable the echo.