what's cleanest way in adding local windows firewall rules with powershell

Question

I have written the following simple script that reads a csv file then iterates through each and adds in some firewall rules to a local machine.

I wanted to know if this the 'cleanest' way of achieving this. (i know there is gpo etc) but I am trying more of my powershell. I'll also try and add a check if the rule names already exist or not.

$rulenames = Import-Csv -Path "C:\temp\newrulenames.csv"

ForEach ($name in $rulenames) {
    New-NetFirewallRule -DisplayName $name.DisplayName -Name $name.Name -Enabled $name.Enabled -Profile $name.Profile -Direction $name.Direction -Action $name.Action -Protocol $name.Protocol -Program $name.Program -EdgeTraversalPolicy $name.EdgeTraversalPolicy
}

Answer 1

GPO seems like the way to go really but since you already are aware of that and are trying out PowerShell...

In cases like this I personally like to use something called splatting (see about_Splatting) since it improves script readability quite a bit in my opinion. For your particular code it could look something like this;

$rulenames = Import-Csv -Path "C:\temp\newrulenames.csv"
foreach($name in $rulenames)
{
    $ruleProps=@{
        DisplayName = $name.DisplayName
        Name = $name.Name
        Enabled = $name.Enabled
        Profile = $name.Profile
        Direction = $name.Direction
        Action = $name.Action
        Protocol = $name.Protocol
        Program = $name.Program
        EdgeTraversalPolicy = $name.EdgeTraversalPolicy
    }
    New-NetFirewallRule @ruleProps
}

And, in order to run some checks (rule name as you mentioned for instance) this could be done right away within the hashtable. For instance you could do something like this;

$ruleProps=@{
    DisplayName = $name.DisplayName
    Name = if(Get-NetFireWallRule -Name $name.Name -ErrorAction SilentlyContinue) { "$($name.Name)-2" } else { $name.name }
    Enabled = $name.Enabled
    Profile = $name.Profile
    Direction = $name.Direction
    Action = $name.Action
    Protocol = $name.Protocol
    Program = $name.Program
    EdgeTraversalPolicy = $name.EdgeTraversalPolicy
}

In this hashtable example we run a check right away if we get a hit on that particular rule name. If it's a hit, we add -2 to the end of the name, else we name it as originally intended.

Alrighty, that was my lunch break - I will check back if you have any follow up questions and double check if I had any typos, sloppy mistakes or whatever, just figured I'd give you an idea of what you can do.

Edit: Well I came back sooner than I had imagined. In the second hashtable example, quite a bit of the improved readability I mentioned in example 1 actually gets lost. Maybe not with only the one name check but certainly so if you run multiple checks. It will most likely still work but - as I said - the readability might suffer.