{"id":17861,"date":"2010-07-04T00:01:00","date_gmt":"2010-07-04T00:01:00","guid":{"rendered":"https:\/\/blogs.technet.microsoft.com\/heyscriptingguy\/2010\/07\/04\/hey-scripting-guy-weekend-scripter-improving-yesterdays-windows-firewall-script\/"},"modified":"2010-07-04T00:01:00","modified_gmt":"2010-07-04T00:01:00","slug":"hey-scripting-guy-weekend-scripter-improving-yesterdays-windows-firewall-script","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/scripting\/hey-scripting-guy-weekend-scripter-improving-yesterdays-windows-firewall-script\/","title":{"rendered":"Hey, Scripting Guy! Weekend Scripter: Improving Yesterday’s Windows Firewall Script"},"content":{"rendered":"

 \nMicrosoft Scripting Guy Ed Wilson here. The Smokey Mountains are about 10 degrees cooler than Charlotte<\/a>, North Carolina<\/a>, is. The problem is that it was nearly 100 degrees Fahrenheit in Charlotte. Anyway, getting to spend some time with my old high school friend has been fun, even if he does not know Windows PowerShell from a seashell. Oh well, he still has good taste in music.\nOn the drive up into the mountains, the Scripting Wife was commenting on the beautiful trees, creeks, and occasional wild animal; I, on the other hand, was thinking of ways to improve my firewall script.\nWhen we arrived at the cabin John had not yet arrived, so I got out my laptop and got to work on my improved firewall script. The Get-EnabledFireWallRules.ps1 script uses an enumeration to parse the protocol instead of displaying a protocol number like the script from yesterday<\/a> did. In addition, the Format-Table<\/strong> cmdlet uses a hash table to perform the lookup for the enumeration value as well as to interpret the direction of the rule. The complete Get-EnabledFireWallRules.ps1 script is shown here.\nGet-EnabledFireWallRules.ps1<\/strong>\nFunction<\/span> <\/span>New-ProtocolEnum<\/span>
<\/span>{<\/span>
<\/span>$enum<\/span> <\/span>=<\/span> ”
namespace myspace 
{ 
public enum protocol
{ 
HOPOPT = 0, ICMPv4 = 1, IGMP = 2, TCP = 6, UDP = 17, IPv6 = 41,
IPv6Route = 43, IPv6Frag = 44 ,GRE = 47, ICMPv6 = 58, IPv6NoNxt = 59,
IPv6Opts = 60, VRRP = 112, PGM = 113, L2TP = 115
}
}
”
<\/span>Add-Type<\/span> <\/span>-TypeDefinition<\/span> <\/span>$enum<\/span> <\/span>-Language<\/span> <\/span>CSharpVersion3<\/span>
<\/span>}<\/span> <\/span>#<\/span>end<\/span> <\/span>function<\/span> <\/span>New-ProtocolEnum<\/span>
<\/span>Function<\/span> <\/span>Test-LoadedEnum<\/span>
<\/span>{<\/span>
<\/span>Param([string]<\/span>$enum<\/span>)<\/span>
<\/span>Try<\/span>
<\/span>{<\/span> 
<\/span>[reflection.assembly]::GetAssembly([<\/span>type<\/span>]<\/span>$enum<\/span>)<\/span> <\/span>|<\/span> <\/span>out-null<\/span>
<\/span>New-Object<\/span> <\/span>psobject<\/span> <\/span>-Property<\/span> <\/span>`<\/span>
<\/span>@{<\/span> “Name” <\/span>=<\/span> <\/span>$enum<\/span>.tostring()<\/span> <\/span>;<\/span> “Loaded” <\/span>=<\/span> <\/span>[bool]<\/span>$true<\/span> <\/span>}<\/span>
<\/span>}<\/span>
<\/span>Catch<\/span> <\/span>[system.exception]<\/span>
<\/span>{<\/span>
<\/span>New-Object<\/span> <\/span>psobject<\/span> <\/span>-Property<\/span> <\/span>`<\/span>
<\/span>@{<\/span> “Name” <\/span>=<\/span> <\/span>$enum<\/span>.tostring()<\/span> <\/span>;<\/span> “Loaded” <\/span>=<\/span> <\/span>[bool]<\/span>$false<\/span> <\/span>}<\/span>
<\/span>}<\/span> 
<\/span>}<\/span> <\/span>#<\/span>end<\/span> <\/span>function<\/span> <\/span>Test-LoadedEnum<\/span>
<\/span>Function<\/span> <\/span>import-Enum<\/span>
<\/span>{<\/span>
<\/span>Param(<\/span>$rtn<\/span>)<\/span>
<\/span>If<\/span> <\/span>(<\/span>$rtn<\/span>.Loaded)<\/span>
<\/span>{<\/span> “$($rtn.name) is loaded” <\/span>}<\/span>
<\/span>else<\/span> <\/span>{<\/span> 
“$($rtn.name) NOT loaded. Loading …” 
<\/span>New-ProtocolEnum<\/span> 
<\/span>}<\/span>
<\/span>}<\/span> <\/span>#<\/span>end<\/span> <\/span>function<\/span> <\/span>import-enum<\/span>
<\/span>Function<\/span> <\/span>Get-FireWallRules<\/span>
<\/span>{<\/span>
<\/span>$fw<\/span> <\/span>=<\/span> <\/span>New-Object<\/span> <\/span>-ComObject<\/span> <\/span>hnetcfg.fwpolicy2<\/span>
<\/span>$currentProfile<\/span> <\/span>=<\/span> <\/span>$fw<\/span>.CurrentProfileTypes<\/span>
<\/span>$fw<\/span>.Rules<\/span> <\/span>|<\/span>
<\/span>Where-Object<\/span> <\/span>{<\/span>$_<\/span>.enabled<\/span> <\/span>-AND<\/span> <\/span>$_<\/span>.Profiles<\/span> <\/span>-eq<\/span> <\/span>$currentProfile<\/span>}<\/span> <\/span>|<\/span> 
<\/span>Sort-Object<\/span> <\/span>-Property<\/span> <\/span>direction<\/span> <\/span>|<\/span> 
<\/span>Format-Table<\/span> <\/span>-Property<\/span> <\/span>localports,<\/span>
<\/span>@{LABEL<\/span>=<\/span>“Protocol”<\/span>;<\/span> <\/span>EXPRESSION<\/span>=<\/span>{[enum]::parse([<\/span>type<\/span>]<\/span>“myspace.protocol”<\/span>,<\/span>$_<\/span>.protocol)}<\/span> <\/span>},<\/span>
<\/span>@{LABEL<\/span>=<\/span>“Direction”<\/span>;<\/span> <\/span>EXPRESSION<\/span>=<\/span>{<\/span> <\/span>SWITCH(<\/span>$_<\/span>.direction){<\/span> <\/span>1<\/span>{<\/span>“in”<\/span>}<\/span> <\/span>2<\/span>{<\/span>“out”<\/span>}}<\/span> <\/span>}<\/span> <\/span>},<\/span>
<\/span>name<\/span> <\/span>-autosize<\/span>
<\/span>}<\/span> <\/span>#<\/span>end<\/span> <\/span>function<\/span> <\/span>Get-FirewallRules<\/span>
<\/span>#<\/span> <\/span>***<\/span> <\/span>ENTRY<\/span> <\/span>POINT<\/span> <\/span>TO<\/span> <\/span>SCRIPT<\/span> <\/span>***<\/span>
<\/span>import-enum<\/span> <\/span>-rtn<\/span> <\/span>(test-LoadedEnum<\/span> <\/span>-enum<\/span> “myspace.protocol”<\/span>)<\/span>
<\/span>Get-FireWallRules<\/span>\nThe New-ProtocolEnum<\/strong> function is used to create the myspace.protocol<\/strong> enumeration. The creation of new enums was discussed in a Weekend Scripter article<\/a> a couple of weeks ago. The mapping of the protocol numbers to names is discussed in a TechNet article in the Library.<\/a> The New-ProtocolEnum<\/strong> function is shown here:\n <\/p>\n

Function<\/span> <\/span>New-ProtocolEnum<\/span>
<\/span>{<\/span>
<\/span>$enum<\/span> <\/span>=<\/span> ”
namespace myspace 
{ 
public enum protocol
{ 
HOPOPT = 0, ICMPv4 = 1, IGMP = 2, TCP = 6, UDP = 17, IPv6 = 41,
IPv6Route = 43, IPv6Frag = 44 ,GRE = 47, ICMPv6 = 58, IPv6NoNxt = 59,
IPv6Opts = 60, VRRP = 112, PGM = 113, L2TP = 115
}
}
”
<\/span> <\/p>\n
Add-Type<\/span> <\/span>-TypeDefinition<\/span> <\/span>$enum<\/span> <\/span>-Language<\/span> <\/span>CSharpVersion3<\/span>
<\/span>}<\/span> <\/span>#<\/span>end<\/span> <\/span>function<\/span> <\/span>New-ProtocolEnum<\/span> <\/span> <\/div>\n<\/p><\/div>\n

The Test-LoadedEnum<\/strong> function is lifted from a recent Weekend Scripter article<\/a> that I wrote while in Hilton Head, South Carolina<\/a>. See that article for a discussion of how it works. The complete Test-LoadedEnum<\/strong> function is shown here:\n <\/p>\n

Function<\/span> <\/span>Test-LoadedEnum<\/span>
<\/span>{<\/span>
<\/span>Param([string]<\/span>$enum<\/span>)<\/span>
<\/span>Try<\/span>
<\/span>{<\/span> 
<\/span>[reflection.assembly]::GetAssembly([<\/span>type<\/span>]<\/span>$enum<\/span>)<\/span> <\/span>|<\/span> <\/span>out-null<\/span>
<\/span>New-Object<\/span> <\/span>psobject<\/span> <\/span>-Property<\/span> <\/span>`<\/span>
<\/span>@{<\/span> “Name” <\/span>=<\/span> <\/span>$enum<\/span>.tostring()<\/span> <\/span>;<\/span> “Loaded” <\/span>=<\/span> <\/span>[bool]<\/span>$true<\/span> <\/span>}<\/span>
<\/span>}<\/span>
<\/span>Catch<\/span> <\/span>[system.exception]<\/span>
<\/span>{<\/span>
<\/span>New-Object<\/span> <\/span>psobject<\/span> <\/span>-Property<\/span> <\/span>`<\/span>
<\/span>@{<\/span> “Name” <\/span>=<\/span> <\/span>$enum<\/span>.tostring()<\/span> <\/span>;<\/span> “Loaded” <\/span>=<\/span> <\/span>[bool]<\/span>$false<\/span> <\/span>}<\/span>
<\/span>}<\/span> 
<\/span>}<\/span> <\/span>#<\/span>end<\/span> <\/span>function<\/span> <\/span>Test-LoadedEnum<\/span> <\/div>\n

I decided to write a function to determine if I need to load the enumeration or not. This removed some of the logic from the beginning of the script. In addition, it provides a completely re-usable function. The Import-Enum<\/strong> function is shown here:\n <\/p>\n

Function<\/span> <\/span>import-Enum<\/span>
<\/span>{<\/span>
<\/span>Param(<\/span>$rtn<\/span>)<\/span>
<\/span>If<\/span> <\/span>(<\/span>$rtn<\/span>.Loaded)<\/span>
<\/span>{<\/span> “$($rtn.name) is loaded” <\/span>}<\/span>
<\/span>else<\/span> <\/span>{<\/span> 
“$($rtn.name) NOT loaded. Loading …” 
<\/span>New-ProtocolEnum<\/span> 
<\/span>}<\/span>
<\/span>}<\/span> <\/span>#<\/span>end<\/span> <\/span>function<\/span> <\/span>import-enum<\/span> <\/div>\n

The Get-FireWallRules<\/strong> function is much like the script from yesterday’s post. The difference is that it tests for the current profile and uses two hash tables to create customized table entries. The one that does the protocol lookup from the myspace.protocol<\/strong> enum is shown here:\n@{LABEL<\/span>=<\/span>“Protocol”<\/span>;<\/span> <\/span>EXPRESSION<\/span>=<\/span>{[enum]::parse([<\/span>type<\/span>]<\/span>“myspace.protocol”<\/span>,<\/span>$_<\/span>.protocol)}<\/span> <\/span>}<\/span>\nThe key was using the system.enum<\/strong> static parse method, the type constraint for the myspace.protocol<\/strong> enum, and passing the protocol number. This technique was discussed in the working with enumerations and values Weekend Scripter article<\/a>. The complete Get-FirewallRules<\/strong> function is shown here:\n <\/p>\n

Function<\/span> <\/span>Get-FireWallRules<\/span>
<\/span>{<\/span>
<\/span>$fw<\/span> <\/span>=<\/span> <\/span>New-Object<\/span> <\/span>-ComObject<\/span> <\/span>hnetcfg.fwpolicy2<\/span>
<\/span>$currentProfile<\/span> <\/span>=<\/span> <\/span>$fw<\/span>.CurrentProfileTypes<\/span>
<\/span>$fw<\/span>.Rules<\/span> <\/span>|<\/span>
<\/span>Where-Object<\/span> <\/span>{<\/span>$_<\/span>.enabled<\/span> <\/span>-AND<\/span> <\/span>$_<\/span>.Profiles<\/span> <\/span>-eq<\/span> <\/span>$currentProfile<\/span>}<\/span> <\/span>|<\/span> 
<\/span>Sort-Object<\/span> <\/span>-Property<\/span> <\/span>direction<\/span> <\/span>|<\/span> 
<\/span>Format-Table<\/span> <\/span>-Property<\/span> <\/span>localports,<\/span>
<\/span>@{LABEL<\/span>=<\/span>“Protocol”<\/span>;<\/span> <\/span>EXPRESSION<\/span>=<\/span>{[enum]::parse([<\/span>type<\/span>]<\/span>“myspace.protocol”<\/span>,<\/span>$_<\/span>.protocol)}<\/span> <\/span>},<\/span>
<\/span>@{LABEL<\/span>=<\/span>“Direction”<\/span>;<\/span> <\/span>EXPRESSION<\/span>=<\/span>{<\/span> <\/span>SWITCH(<\/span>$_<\/span>.direction){<\/span> <\/span>1<\/span>{<\/span>“in”<\/span>}<\/span> <\/span>2<\/span>{<\/span>“out”<\/span>}}<\/span> <\/span>}<\/span> <\/span>},<\/span>
<\/span>name<\/span> <\/span>-autosize<\/span>
<\/span>}<\/span> <\/span>#<\/span>end<\/span> <\/span>function<\/span> <\/span>Get-FirewallRules<\/span> <\/div>\n

The entry point to the script calls the Import-Enum<\/strong> function while passing the result from the Test-LoadedEnum<\/strong> function. Next, it calls the Get-FirewallRules<\/strong> function. This is shown here:\n <\/p>\n

import-enum<\/span> <\/span>-rtn<\/span> <\/span>(test-LoadedEnum<\/span> <\/span>-enum<\/span> “myspace.protocol”<\/span>)<\/span>
<\/span>Get-FireWallRules<\/span> <\/div>\n

Ed Wilson and Craig Liebendorfer, Script<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

  Microsoft Scripting Guy Ed Wilson here. The Smokey Mountains are about 10 degrees cooler than Charlotte, North Carolina, is. The problem is that it was nearly 100 degrees Fahrenheit in Charlotte. Anyway, getting to spend some time with my old high school friend has been fun, even if he does not know Windows PowerShell […]<\/p>\n","protected":false},"author":595,"featured_media":87096,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[148,161,3,4,63,61,45],"class_list":["post-17861","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-scripting","tag-enum","tag-firewall","tag-scripting-guy","tag-scripting-techniques","tag-security","tag-weekend-scripter","tag-windows-powershell"],"acf":[],"blog_post_summary":"

  Microsoft Scripting Guy Ed Wilson here. The Smokey Mountains are about 10 degrees cooler than Charlotte, North Carolina, is. The problem is that it was nearly 100 degrees Fahrenheit in Charlotte. Anyway, getting to spend some time with my old high school friend has been fun, even if he does not know Windows PowerShell […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts\/17861","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/users\/595"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/comments?post=17861"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts\/17861\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/media\/87096"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/media?parent=17861"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/categories?post=17861"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/tags?post=17861"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

When the Get-EnabledFireWallRules.ps1 script runs, the output is displayed that is shown in the following image.\n\"Image<\/a>\nThe cool thing about all this is that it provides an excellent example for using our recent discussion of working with enums<\/a>. Well, I think I hear the “old folks” stirring inside the cabin. I believe I overheard Becky and the Scripting Wife talking about making pancakes<\/a>, so perhaps I will go inside and see if they need a taste tester. I hope you have a great weekend.\nIf you want to know exactly what we will be looking at tomorrow, follow us on Twitter<\/a> or Facebook<\/a>. If you have any questions, send e-mail to us at scripter@microsoft.com<\/a>, or post your questions on the Official Scripting Guys Forum<\/a>. See you tomorrow. Until then, peace.\n <\/p>\n