functions/Test-DbaSpn.ps1

#ValidationTags#FlowControl,Pipeline#
function Test-DbaSpn {
    <#
        .SYNOPSIS
            Test-DbaSpn will determine what SPNs *should* be set for a given server (and any instances of SQL running on it) and return
            whether the SPNs are set or not.
 
        .DESCRIPTION
            This function is designed to take in a server name(s) and attempt to determine required SPNs. It was initially written to mimic the (previously)
            broken functionality of the Microsoft Kerberos Configuration manager and SQL Server 2016. The functon will connect to a remote server and,
            through WMI, discover all running intances of SQL Server. For any instances with TCP/IP enabled, the script will determine which port(s)
            the instances are listening on and generate the required SPNs. For named instances NOT using dynamic ports, the script will generate a port-
            based SPN for those instances as well. At a minimum, the script will test a base, port-less SPN for each instance discovered.
 
            Once the required SPNs are generated, the script will connect to Active Directory and search for any of the SPNs (if any) that are already
            set.
 
            The function will return a custom object(s) that contains the server name checked, the instance name discovered, the account the service is
            running under, and what the "required" SPN should be. It will also return a boolean property indicating if the SPN is set in Active Directory
            or not.
 
        .PARAMETER ComputerName
            The computer you want to discover any SQL Server instances on. This parameter is required.
 
        .PARAMETER Credential
            The credential you want to use to connect to the remote server and active directory.
 
        .PARAMETER Silent
            If this switch is enabled, the internal messaging functions will be silenced.
 
        .NOTES
            Tags: SPN
            Author: Drew Furgiuele (@pittfurg), http://www.port1433.com
            Editor: niphlod
 
            Website: https://dbatools.io
            Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
            License: GNU GPL v3 https://opensource.org/licenses/GPL-3.0
 
        .LINK
            https://dbatools.io/Test-DbaSpn
 
        .EXAMPLE
            Test-DbaSpn -ComputerName SQLSERVERA -Credential (Get-Credential)
 
            Connects to a computer (SQLSERVERA) and queries WMI for all SQL instances and return "required" SPNs. It will then take each SPN it generates
            and query Active Directory to make sure the SPNs are set.
 
        .EXAMPLE
            Test-DbaSpn -ComputerName SQLSERVERA,SQLSERVERB -Credential (Get-Credential)
 
            Connects to multiple computers (SQLSERVERA, SQLSERVERB) and queries WMI for all SQL instances and return "required" SPNs.
            It will then take each SPN it generates and query Active Directory to make sure the SPNs are set.
 
        .EXAMPLE
            Test-DbaSpn -ComputerName SQLSERVERC -Credential (Get-Credential)
 
            Connects to a computer (SQLSERVERC) on a specified and queries WMI for all SQL instances and return "required" SPNs.
            It will then take each SPN it generates and query Active Directory to make sure the SPNs are set. Note that the credential you pass must have be a valid login with appropriate rights on the domain
    #>

    [cmdletbinding()]
    param (
        [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [DbaInstance[]]$ComputerName,
        [PSCredential]$Credential,
        [switch]$Silent
    )
    begin {
        # spare the cmdlet to search for the same account over and over
        $resultCache = @{}
    }
    process {
        foreach ($computer in $ComputerName) {
            try {
                $resolved = Resolve-DbaNetworkName -ComputerName $computer.ComputerName -Credential $Credential -ErrorAction Stop
            }
            catch {
                $resolved = Resolve-DbaNetworkName -ComputerName $computer.ComputerName -Turbo
            }

            if ($null -eq $resolved.IPAddress) {
                Write-Message -Level Warning -Message "Cannot resolve IP address, moving on."
                continue
            }

            $hostEntry = $resolved.FullComputerName

            Write-Message -Message "Resolved ComputerName to FQDN: $hostEntry" -Level Verbose

            $Scriptblock = {

                function Convert-SqlVersion {
                    [cmdletbinding()]
                    param (
                        [version]$version
                    )

                    switch ($version.Major) {
                        9 { "SQL Server 2005" }
                        10 {
                            if ($version.Minor -eq 0) {
                                "SQL Server 2008"
                            }
                            else {
                                "SQL Server 2008 R2"
                            }
                        }
                        11 { "SQL Server 2012" }
                        12 { "SQL Server 2014" }
                        13 { "SQL Server 2016" }
                        14 { "SQL Server 2017" }
                        default { $version }
                    }
                }

                $spns = @()
                $servereName = $args[0]
                $hostEntry = $args[1]
                $instanceName = $args[2]
                $instanceCount = $wmi.ServerInstances.Count

                <# DO NOT use Write-Message as this is inside of a script block #>
                Write-Verbose "Found $instanceCount instances"

                foreach ($instance in $wmi.ServerInstances) {
                    $spn = [pscustomobject] @{
                        ComputerName           = $servereName
                        InstanceName           = $instanceName
                        #SKUNAME
                        SqlProduct             = $null
                        InstanceServiceAccount = $null
                        RequiredSPN            = $null
                        IsSet                  = $false
                        Cluster                = $false
                        TcpEnabled             = $false
                        Port                   = $null
                        DynamicPort            = $false
                        Warning                = "None"
                        Error                  = "None"
                        # for piping
                        Credential             = $Credential
                    }

                    $spn.InstanceName = $instance.Name
                    $instanceName = $spn.InstanceName

                    <# DO NOT use Write-Message as this is inside of a script block #>
                    Write-Verbose "Parsing $instanceName"

                    $services = $wmi.Services | Where-Object DisplayName -EQ "SQL Server ($instanceName)"
                    $spn.InstanceServiceAccount = $services.ServiceAccount
                    $spn.Cluster = ($services.advancedproperties | Where-Object Name -EQ 'Clustered').Value

                    if ($spn.Cluster) {
                        $hostEntry = ($services.advancedproperties | Where-Object Name -EQ 'VSNAME').Value.ToLower()
                        <# DO NOT use Write-Message as this is inside of a script block #>
                        Write-Verbose "Found cluster $hostEntry"
                        $hostEntry = ([System.Net.Dns]::GetHostEntry($hostEntry)).HostName
                        $spn.ComputerName = $hostEntry
                    }

                    $rawVersion = [version]($services.AdvancedProperties | Where-Object Name -EQ 'VERSION').Value

                    $version = Convert-SqlVersion $rawVersion
                    $skuName = ($services.AdvancedProperties | Where-Object Name -EQ 'SKUNAME').Value

                    $spn.SqlProduct = "$version $skuName"

                    #is tcp enabled on this instance? If not, we don't need an spn, son
                    if ((($instance.ServerProtocols | Where-Object { $_.Displayname -eq "TCP/IP" }).ProtocolProperties | Where-Object { $_.Name -eq "Enabled" }).Value -eq $true) {
                        <# DO NOT use Write-Message as this is inside of a script block #>
                        Write-Verbose "TCP is enabled, gathering SPN requirements"
                        $spn.TcpEnabled = $true
                        #Each instance has a default SPN of MSSQLSvc\<fqdn> or MSSSQLSvc\<fqdn>:Instance
                        if ($instance.Name -eq "MSSQLSERVER") {
                            $spn.RequiredSPN = "MSSQLSvc/$hostEntry"
                        }
                        else {
                            $spn.RequiredSPN = "MSSQLSvc/" + $hostEntry + ":" + $instance.Name
                        }
                    }

                    $spns += $spn
                }
                # Now, for each spn, do we need a port set? Only if TCP is enabled and NOT DYNAMIC!
                foreach ($spn in $spns) {
                    $ports = @()

                    $ips = (($wmi.ServerInstances | Where-Object { $_.Name -eq $spn.InstanceName }).ServerProtocols | Where-Object { $_.DisplayName -eq "TCP/IP" -and $_.IsEnabled -eq "True" }).IpAddresses
                    $ipAllPort = $null
                    foreach ($ip in $ips) {
                        if ($ip.Name -eq "IPAll") {
                            $ipAllPort = ($ip.IPAddressProperties | Where-Object { $_.Name -eq "TCPPort" }).Value
                            if (($ip.IpAddressProperties | Where-Object { $_.Name -eq "TcpDynamicPorts" }).Value -ne "") {
                                $ipAllPort = ($ip.IPAddressProperties | Where-Object { $_.Name -eq "TcpDynamicPorts" }).Value + "d"
                            }
                        }
                        else {
                            $enabled = ($ip.IPAddressProperties | Where-Object { $_.Name -eq "Enabled" }).Value
                            $active = ($ip.IPAddressProperties | Where-Object { $_.Name -eq "Active" }).Value
                            $tcpDynamicPorts = ($ip.IPAddressProperties | Where-Object { $_.Name -eq "TcpDynamicPorts" }).Value
                            if ($enabled -and $active -and $tcpDynamicPorts -eq "") {
                                $ports += ($ip.IPAddressProperties | Where-Object { $_.Name -eq "TCPPort" }).Value
                            }
                            elseif ($enabled -and $active -and $tcpDynamicPorts -ne "") {
                                $ports += $ipAllPort + "d"
                            }
                        }
                    }
                    if ($ipAllPort -ne "") {
                        #IPAll overrides any set ports. Not sure why that's the way it is?
                        $ports = $ipAllPort
                    }

                    $ports = $ports | Select-Object -Unique
                    foreach ($port in $ports) {
                        $newspn = $spn.PSObject.Copy()
                        if ($port -like "*d") {
                            $newspn.Port = ($port.replace("d", ""))
                            $newspn.RequiredSPN = $newspn.RequiredSPN.Replace($newSPN.InstanceName, $newspn.Port)
                            $newspn.DynamicPort = $true
                            $newspn.Warning = "Dynamic port is enabled"
                        }
                        else {
                            #If this is a named instance, replace the instance name with a port number (for non-dynamic ported named instances)
                            $newspn.Port = $port
                            $newspn.DynamicPort = $false

                            if ($newspn.InstanceName -eq "MSSQLSERVER") {
                                $newspn.RequiredSPN = $newspn.RequiredSPN + ":" + $port
                            }
                            else {
                                $newspn.RequiredSPN = $newspn.RequiredSPN.Replace($newSPN.InstanceName, $newspn.Port)
                            }
                        }
                        $spns += $newspn
                    }
                }
                $spns
            }

            Write-Message -Message "Attempting to connect to SQL WMI on remote computer " -Level Verbose

            try {
                $spns = Invoke-ManagedComputerCommand -ComputerName $hostEntry -ScriptBlock $Scriptblock -ArgumentList $resolved.FullComputerName, $hostEntry, $computer.InstanceName -Credential $Credential -ErrorAction Stop
            }
            catch {
                Stop-Function -Message "Couldn't connect to $computer" -ErrorRecord $_ -Continue
            }

            #Now query AD for each required SPN
            foreach ($spn in $spns) {
                $searchfor = 'User'
                if ($spn.InstanceServiceAccount -eq 'LocalSystem' -or $spn.InstanceServiceAccount -like 'NT SERVICE\*') {
                    Write-Message -Level Verbose -Message "Virtual account detected, changing target registration to computername"
                    $spn.InstanceServiceAccount = "$($resolved.Domain)\$($resolved.ComputerName)$"
                    $searchfor = 'Computer'
                } elseif ($spn.InstanceServiceAccount -like '*\*$') {
                    Write-Message -Level Verbose -Message "Managed Service Account detected"
                    $searchfor = 'Computer'
                }
                
                $serviceAccount = $spn.InstanceServiceAccount
                # spare the cmdlet to search for the same account over and over
                if ($spn.InstanceServiceAccount -notin $resultCache.Keys) {
                    Write-Message -Message "Searching for $serviceAccount" -Level Verbose
                    try {
                        $result = Get-DbaADObject -ADObject $serviceAccount -Type $searchfor -Credential $Credential -Silent
                        $resultCache[$spn.InstanceServiceAccount] = $result
                    }
                    catch {
                        if (![System.String]::IsNullOrEmpty($spn.InstanceServiceAccount)) {
                            Write-Message -Message "AD lookup failure. This may be because the domain cannot be resolved for the SQL Server service account ($serviceAccount)." -Level Warning
                        }
                    }
                }
                else {
                    $result = $resultCache[$spn.InstanceServiceAccount]
                }
                if ($result.Count -gt 0) {
                    try {
                        $results = $result.GetUnderlyingObject()
                        if ($results.Properties.servicePrincipalName -contains $spn.RequiredSPN) {
                            $spn.IsSet = $true
                        }
                    }
                    catch {
                        Write-Message -Message "The SQL Service account ($serviceAccount) has been found, but you don't have enough permission to inspect its SPNs" -Level Warning
                        continue
                    }
                }
                else {
                    Write-Message -Level Warning -Message "SQL Service account not found. Results may not be accurate."
                    $spn
                    continue
                }
                if (!$spn.IsSet -and $spn.TcpEnabled) {
                    $spn.Error = "SPN missing"
                }

                $spn | Select-DefaultView -ExcludeProperty Credential, DomainName
            }
        }
    }
}