VaultServer

1.0.1

Private/ResolveHost.ps1

function ResolveHost {
    [CmdletBinding()]
    Param(
        [Parameter(Mandatory=$True)]
        [string]$HostNameOrIP
    )

    ##### BEGIN Main Body #####

    $RemoteHostNetworkInfoArray = @()
    if (!$(TestIsValidIPAddress -IPAddress $HostNameOrIP)) {
        try {
            $HostNamePrep = $HostNameOrIP
            [System.Collections.ArrayList]$RemoteHostArrayOfIPAddresses = @()
            $IPv4AddressFamily = "InterNetwork"
            $IPv6AddressFamily = "InterNetworkV6"

            $ResolutionInfo = [System.Net.Dns]::GetHostEntry($HostNamePrep)
            $ResolutionInfo.AddressList | Where-Object {
                $_.AddressFamily -eq $IPv4AddressFamily
            } | foreach {
                if ($RemoteHostArrayOfIPAddresses -notcontains $_.IPAddressToString) {
                    $null = $RemoteHostArrayOfIPAddresses.Add($_.IPAddressToString)
                }
            }
        }
        catch {
            Write-Verbose "Unable to resolve $HostNameOrIP when treated as a Host Name (as opposed to IP Address)!"

            if ($HostNameOrIP -match "\.") {
                try {
                    $HostNamePrep = $($HostNameOrIP -split "\.")[0]
                    Write-Verbose "Trying to resolve $HostNameOrIP using only HostName: $HostNamePrep!"

                    [System.Collections.ArrayList]$RemoteHostArrayOfIPAddresses = @()
                    $ResolutionInfo = [System.Net.Dns]::GetHostEntry($HostNamePrep)
                    $ResolutionInfo.AddressList | Where-Object {
                        $_.AddressFamily -eq $IPv4AddressFamily
                    } | foreach {
                        if ($RemoteHostArrayOfIPAddresses -notcontains $_.IPAddressToString) {
                            $null = $RemoteHostArrayOfIPAddresses.Add($_.IPAddressToString)
                        }
                    }
                }
                catch {
                    Write-Verbose "Unable to resolve $HostNamePrep!"
                }
            }
        }
    }
    if (TestIsValidIPAddress -IPAddress $HostNameOrIP) {
        try {
            $HostIPPrep = $HostNameOrIP
            [System.Collections.ArrayList]$RemoteHostArrayOfIPAddresses = @()
            $null = $RemoteHostArrayOfIPAddresses.Add($HostIPPrep)

            $ResolutionInfo = [System.Net.Dns]::GetHostEntry($HostIPPrep)

            [System.Collections.ArrayList]$RemoteHostFQDNs = @() 
            $null = $RemoteHostFQDNs.Add($ResolutionInfo.HostName)
        }
        catch {
            Write-Verbose "Unable to resolve $HostNameOrIP when treated as an IP Address (as opposed to Host Name)!"
        }
    }

    if ($RemoteHostArrayOfIPAddresses.Count -eq 0) {
        Write-Error "Unable to determine IP Address of $HostNameOrIP! Halting!"
        $global:FunctionResult = "1"
        return
    }

    # At this point, we have $RemoteHostArrayOfIPAddresses...
    [System.Collections.ArrayList]$RemoteHostFQDNs = @()
    foreach ($HostIP in $RemoteHostArrayOfIPAddresses) {
        try {
            $FQDNPrep = [System.Net.Dns]::GetHostEntry($HostIP).HostName
        }
        catch {
            Write-Verbose "Unable to resolve $HostIP. No PTR Record? Please check your DNS config."
            continue
        }
        if ($RemoteHostFQDNs -notcontains $FQDNPrep) {
            $null = $RemoteHostFQDNs.Add($FQDNPrep)
        }
    }

    if ($RemoteHostFQDNs.Count -eq 0) {
        $null = $RemoteHostFQDNs.Add($ResolutionInfo.HostName)
    }

    [System.Collections.ArrayList]$HostNameList = @()
    [System.Collections.ArrayList]$DomainList = @()
    foreach ($fqdn in $RemoteHostFQDNs) {
        $PeriodCheck = $($fqdn | Select-String -Pattern "\.").Matches.Success
        if ($PeriodCheck) {
            $HostName = $($fqdn -split "\.")[0]
            $Domain = $($fqdn -split "\.")[1..$($($fqdn -split "\.").Count-1)] -join '.'
        }
        else {
            $HostName = $fqdn
            $Domain = "Unknown"
        }

        $null = $HostNameList.Add($HostName)
        $null = $DomainList.Add($Domain)
    }

    if ($RemoteHostFQDNs[0] -eq $null -and $HostNameList[0] -eq $null -and $DomainList -eq "Unknown" -and $RemoteHostArrayOfIPAddresses) {
        [System.Collections.ArrayList]$SuccessfullyPingedIPs = @()
        # Test to see if we can reach the IP Addresses
        foreach ($ip in $RemoteHostArrayOfIPAddresses) {
            try {
                $null = [System.Net.NetworkInformation.Ping]::new().Send($ip,1000)
                $null = $SuccessfullyPingedIPs.Add($ip)
            }
            catch {
                Write-Verbose "Unable to ping $ip..."
                continue
            }
        }
    }

    $FQDNPrep = if ($RemoteHostFQDNs) {$RemoteHostFQDNs[0]} else {$null}
    if ($FQDNPrep -match ',') {
        $FQDN = $($FQDNPrep -split ',')[0]
    }
    else {
        $FQDN = $FQDNPrep
    }

    $DomainPrep = if ($DomainList) {$DomainList[0]} else {$null}
    if ($DomainPrep -match ',') {
        $Domain = $($DomainPrep -split ',')[0]
    }
    else {
        $Domain = $DomainPrep
    }

    $IPAddressList = [System.Collections.ArrayList]@($(if ($SuccessfullyPingedIPs) {$SuccessfullyPingedIPs} else {$RemoteHostArrayOfIPAddresses}))
    $HName = if ($HostNameList) {$HostNameList[0].ToLowerInvariant()} else {$null}

    if ($SuccessfullyPingedIPs.Count -eq 0 -and !$FQDN -and !$HostName -and !$Domain) {
        Write-Error "Unable to resolve $HostNameOrIP! Halting!"
        $global:FunctionResult = "1"
        return
    }

    [pscustomobject]@{
        IPAddressList   = $IPAddressList
        PingSuccess     = $($SuccessfullyPingedIPs.Count -gt 0)
        FQDN            = $FQDN
        HostName        = $HName
        Domain          = $Domain
    }

    ##### END Main Body #####

}