重复的Windows防火墙规则（Netsh AdvFirewall防火墙）

Question

I've noticed that when we create a firewall rule through netsh advfirewall firewall , it can be run multiple times, creating multiple identical firewall rules.

Is there any way of checking if the firewall rule exists before attempting to create a new one?

Answer 1

检查规则“myrule”是否不存在

netsh advfirewall firewall show rule name="myrule" | findstr "no rules"

Answer 2

I managed to get this going through PowerShell's Network Security Cmdlets, the following code will check for a named firewall rule along with a specified local port, if it finds an entry, it does not create the rule. If it does not find an entry, it will create the rule

$firewallPort = ""
$firewallRuleName = ""

write-host "Checking for '$firewallRuleName' firewall rule on port '$firewallPort' now...."
if ($(Get-NetFirewallRule –DisplayName $firewallRuleName | Get-NetFirewallPortFilter | Where { $_.LocalPort -eq $firewallPort }))
{
    write-host "Firewall rule for '$firewallRuleName' on port '$firewallPort' already exists, not creating new rule"
}
else
{
    write-host "Firewall rule for '$firewallRuleName' on port '$firewallPort' does not already exist, creating new rule now..."
    New-NetFirewallRule -DisplayName $firewallRuleName -Direction Inbound -Profile Domain,Private,Public -Action Allow -Protocol TCP -LocalPort $firewallPort -RemoteAddress Any
    write-host "Firewall rule for '$firewallRuleName' on port '$firewallPort' created successfully"
}

Answer 3

To expand on @Oleg's answer, here is what I use. Replace the ... according to the criteria for your rule.

set name="my rule"
netsh advfirewall firewall show rule name=!name! >nul
if errorlevel 1 (
    echo Adding firewall rule !name!
    netsh advfirewall firewall add rule name=!name! ...
)

Answer 4

Get-Command -Module NetSecurity
get-help Get-NetFirewallRule -full