Windows Server 2012 : Managing networking using Windows PowerShell (part 1) - Identifying networking cmdlets

You could start by using the Get-Command cmdlet to search for all Windows PowerShell cmdlets and functions that have the string “net” in their names. This generates a lot of output, however, as shown here:

PS C:\> Get-Command *net*

CommandType     Name                                               ModuleName
-----------     ----                                               ----------
Function        Add-NetIPHttpsCertBinding                          NetworkTransition
Function        Add-NetLbfoTeamMember                              NetLbfo
Function        Add-NetLbfoTeamNic                                 NetLbfo
Function        Add-NetSwitchTeamMember                            NetSwitchTeam
Function        Copy-NetFirewallRule                               NetSecurity
Function        Copy-NetIPsecMainModeCryptoSet                     NetSecurity
Function        Copy-NetIPsecMainModeRule                          NetSecurity
Function        Copy-NetIPsecPhase1AuthSet                         NetSecurity
Function        Copy-NetIPsecPhase2AuthSet                         NetSecurity
Function        Copy-NetIPsecQuickModeCryptoSet                    NetSecurity
Function        Copy-NetIPsecRule                                  NetSecurity
Function        Disable-NetAdapter                                 NetAdapter
Function        Disable-NetAdapterBinding                          NetAdapter
Function        Disable-NetAdapterChecksumOffload                  NetAdapter
Function        Disable-NetAdapterEncapsulatedPacketTaskOffload    NetAdapter
Function        Disable-NetAdapterIPsecOffload                     NetAdapter
...

From the preceding output, you can see there are several Windows PowerShell modules that perform network-related actions. To see this more clearly, the following commands take the preceding output, sort it by module name, and remove duplicates:

PS C:\> Get-Command *net* | Sort-Object ModuleName | Format-Table ModuleName `
-HideTableHeaders | Out-String | Out-File c:\data\test.txt
PS C:\> Get-Content C:\data\test.txt | Get-Unique


ActiveDirectory
BranchCache
DnsServer
MsDtc
NetAdapter
NetConnection
NetLbfo
NetQos
NetSecurity
NetSwitchTeam
NetTCPIP
NetworkTransition
NFS
SmbShare

To investigate the NetTCPIP module further, you can use the –Module parameter of Get-Command to list all cmdlets and functions contained in this module:

PS C:\> Get-Command -Module NetTCPIP | Sort-Object Name | Format-Table Name

Name
----
Get-NetIPAddress
Get-NetIPConfiguration
Get-NetIPInterface
Get-NetIPv4Protocol
Get-NetIPv6Protocol
Get-NetNeighbor
Get-NetOffloadGlobalSetting
Get-NetPrefixPolicy
Get-NetRoute
Get-NetTCPConnection
Get-NetTCPSetting
Get-NetTransportFilter
Get-NetUDPEndpoint
Get-NetUDPSetting
New-NetIPAddress
New-NetNeighbor
New-NetRoute
New-NetTransportFilter
Remove-NetIPAddress
Remove-NetNeighbor
Remove-NetRoute
Remove-NetTransportFilter
Set-NetIPAddress
Set-NetIPInterface
Set-NetIPv4Protocol
Set-NetIPv6Protocol
Set-NetNeighbor
Set-NetOffloadGlobalSetting
Set-NetRoute
Set-NetTCPSetting
Set-NetUDPSetting

At this point, you can begin using Get-Help to learn about the syntax of NetTCPIP cmdlets you’re interested in and to see some examples of their usage. Unfortunately for administrators who are not that familiar with Windows PowerShell, the syntax displayed when you use Get-Help with a cmdlet can appear daunting. For example, consider a scenario where you have a web server running Windows Server 2012 and you want to add a second IP address to a network adapter on the server.

You might guess from the output of Get-Command –Module NetTCPIP shown previously that New-NetIPAddress is the cmdlet you use to perform this task, and you would be correct. But to the Windows PowerShell beginner, the syntax from Get-Help New-NetIPAddress might look quite confusing:

Parameter Set: ByInterfaceAlias
New-NetIPAddress -InterfaceAlias <String> [-AddressFamily <AddressFamily> ] [-AsJob]
[-CimSession <CimSession[]> ] [-DefaultGateway <String> ] [-IPv4Address <String> ]
[-IPv6Address <String> ] [-PassThru] [-PreferredLifetime <TimeSpan> ]
[-PrefixLength <Byte> ] [-PrefixOrigin <PrefixOrigin> ] [-SkipAsSource <Boolean> ]
[-Store <Store> ] [-SuffixOrigin <SuffixOrigin> ] [-ThrottleLimit <Int32> ]
[-Type <Type> ] [-ValidLifetime <TimeSpan> ] [-Confirm] [-WhatIf] [ <CommonParameters>]

Parameter Set: ByIfIndexOrIfAlias
New-NetIPAddress [-AddressFamily <AddressFamily> ] [-AsJob]
[-CimSession <CimSession[]> ] [-DefaultGateway <String> ] [-InterfaceAlias <String> ]
[-InterfaceIndex <UInt32> ] [-IPv4Address <String> ] [-IPv6Address <String> ]
[-PassThru] [-PreferredLifetime <TimeSpan> ] [-PrefixLength <Byte> ]
[-PrefixOrigin <PrefixOrigin> ] [-SkipAsSource <Boolean> ] [-Store <Store> ]
[-SuffixOrigin <SuffixOrigin> ] [-ThrottleLimit <Int32> ] [-Type <Type> ]
[-ValidLifetime <TimeSpan> ] [-Confirm] [-WhatIf] [ <CommonParameters>]

Fortunately, the new Show-Command cmdlet in Windows Server 2012 can help make the syntax of Windows PowerShell cmdlets easier to understand and use. Start typing the following command:

PS C:\> Show-Command New-NetIPAddress

When you run the preceding command, the properties page shown in Figure 1 opens to show you the different parameters you can use with the New-NetIPAddress cmdlet. Parameters such as InterfaceAlias and IPAddress that are marked with an asterisk are mandatory; those not marked this way are optional.

Figure 1. The Show-Command properties page for the New-NetIPAddress cmdlet.

Clearly, to add a new IP address you first need to know the alias or index of the network interface to which you want to add the address. To find the interfaces on the system, you could use Get-Command *interface* to find all cmdlets that include “interface” in their name. Of the eight cmdlets displayed when you run this command, the cmdlet Get-NetIPInterface is the one you are looking for, and running this cmdlet displays a list of all interfaces on the server:

PS C:\> Get-NetIPInterface

ifIndex InterfaceAlias             AddressFamily NlMtu(Bytes) InterfaceMetric Dhcp
------- --------------             ------------- ------------ --------------- ----
12      Ethernet                   IPv6                  1500               5 Disabled
14      Teredo Tunneling Pseudo... IPv6                  1280              50 Disabled
13      isatap.{4B8DC8AE-DE20-4... IPv6                  1280              50 Disabled
1       Loopback Pseudo-Interfa.   IPv6            4294967295              50 Disabled
12      Ethernet                   IPv4                  1500               5 Disabled
1       Loopback Pseudo-Interfa.   IPv4            4294967295              50 Disabled

From the preceding command output, you can see that the interface you are looking for is identified by the alias “Ethernet.” To view the existing TCP/IP configuration of this interface, you can use the –InterfaceAlias with the Get-NetIPAddress cmdlet as follows:

PS C:\> Get-NetIPAddress -InterfaceAlias Ethernet



IPAddress         : fe80::cf8:11a1:2e3:d9bc%12
InterfaceIndex    : 12
InterfaceAlias    : Ethernet
AddressFamily     : IPv6
Type              : Unicast
PrefixLength      : 64
PrefixOrigin      : WellKnown
SuffixOrigin      : Link
AddressState      : Preferred
ValidLifetime     : Infinite ([TimeSpan]::MaxValue)
PreferredLifetime : Infinite ([TimeSpan]::MaxValue)
SkipAsSource      : False
PolicyStore       : ActiveStore

IPAddress         : 172.16.11.236
InterfaceIndex    : 12
InterfaceAlias    : Ethernet
AddressFamily     : IPv4
Type              : Unicast
PrefixLength      : 24
PrefixOrigin      : Manual
SuffixOrigin      : Manual
AddressState      : Preferred
ValidLifetime     : Infinite ([TimeSpan]::MaxValue)
PreferredLifetime : Infinite ([TimeSpan]::MaxValue)
SkipAsSource      : False
PolicyStore       : ActiveStore

The preceding command output shows that the Ethernet interface currently has 172.16.11.236/24 as its IPv4 address and Classless Inter-Domain Routing (CIDR) prefix.

Returning to the open properties page displayed by Show-Command New-NetIPAddress, you can add a second IP address to the interface by specifying the parameter values shown in Figure 2.

Figure 2. Adding the address 172.16.11.237/24 to the interface named Ethernet.

If you click Copy in the properties page shown in Figure 2, the command is copied to the clipboard. The resulting command looks like this:

New-NetIPAddress -InterfaceAlias Ethernet -IPAddress 172.16.11.237 `
-AddressFamily IPv4 -PrefixLength 24

If you click Run, the command executes. By using –InterfaceAlias with the Get-NetIPAddress cmdlet again, you can verify that the command accomplished the desired result:

PS C:\> Get-NetIPAddress -InterfaceAlias Ethernet



IPAddress         : fe80::cf8:11a1:2e3:d9bc%12
InterfaceIndex    : 12
InterfaceAlias    : Ethernet
AddressFamily     : IPv6
Type              : Unicast
PrefixLength      : 64
PrefixOrigin      : WellKnown
SuffixOrigin      : Link
AddressState      : Preferred
ValidLifetime     : Infinite ([TimeSpan]::MaxValue)
PreferredLifetime : Infinite ([TimeSpan]::MaxValue)
SkipAsSource      : False
PolicyStore       : ActiveStore

IPAddress         : 172.16.11.237
InterfaceIndex    : 12
InterfaceAlias    : Ethernet
AddressFamily     : IPv4
Type              : Unicast
PrefixLength      : 24
PrefixOrigin      : Manual
SuffixOrigin      : Manual
AddressState      : Preferred
ValidLifetime     : Infinite ([TimeSpan]::MaxValue)
PreferredLifetime : Infinite ([TimeSpan]::MaxValue)
SkipAsSource      : False
PolicyStore       : ActiveStore

IPAddress         : 172.16.11.236
InterfaceIndex    : 12
InterfaceAlias    : Ethernet
AddressFamily     : IPv4
Type              : Unicast
PrefixLength      : 24
PrefixOrigin      : Manual
SuffixOrigin      : Manual
AddressState      : Preferred
ValidLifetime     : Infinite ([TimeSpan]::MaxValue)
PreferredLifetime : Infinite ([TimeSpan]::MaxValue)
SkipAsSource      : False
PolicyStore       : ActiveStore

Opening the Advanced TCP/IP Settings for the interface from the Network Connections folder confirms the result. (See Figure 3.)

Figure 3. The Advanced TCP/IP Settings dialog box confirms that the second IP address was successfully added to the interface.