[CmdletBinding()]
param(
    [string]$ZoneName = 'lci.lasalle.mx',
    [string]$RecordName = 'sgu-auth',
    [ipaddress]$IPv4Address = '192.168.50.10',

    [ipaddress[]]$ExternalForwarders = @()
)

$ErrorActionPreference = 'Stop'
$existing = Get-DnsServerResourceRecord -ZoneName $ZoneName -Name $RecordName -RRType A -ErrorAction SilentlyContinue
if ($existing) {
    $current = @($existing.RecordData.IPv4Address.IPAddressToString)
    if ($current -notcontains $IPv4Address.IPAddressToString) {
        throw "$RecordName.$ZoneName already exists with a different address: $($current -join ', ')."
    }
}
else {
    Add-DnsServerResourceRecordA -ZoneName $ZoneName -Name $RecordName -IPv4Address $IPv4Address
}

if ($ExternalForwarders.Count -gt 0) {
    Set-DnsServerForwarder -IPAddress $ExternalForwarders -UseRootHint $false
    Clear-DnsServerCache -Force
    Clear-DnsClientCache
}

[pscustomobject]@{
    BrokerRecord = Resolve-DnsName "$RecordName.$ZoneName" | Select-Object Name, Type, IPAddress
    ExternalForwarders = @(Get-DnsServerForwarder | Select-Object -ExpandProperty IPAddress | ForEach-Object IPAddressToString)
}