Test Domain Name Resolution against Popular DNS Servers

test-public-dns-domain-resolution.ps1

# Define the list of domains to test
$domains = @("google.com", "simeononsecurity.com", "github.com")

# Define a list of public DNS servers, including those with ad and tracker blocking, and major ISPs
$dnsServers = @{
    "Google" = @("8.8.8.8", "8.8.4.4")
    "Control D" = @("76.76.2.0", "76.76.10.0")
    "Quad9" = @("9.9.9.9", "149.112.112.112")
    "OpenDNS Home" = @("208.67.222.222", "208.67.220.220")
    "Cloudflare" = @("1.1.1.1", "1.0.0.1")
    "AdGuard DNS" = @("94.140.14.14", "94.140.15.15")
    "CleanBrowsing" = @("185.228.168.9", "185.228.169.9")
    "Alternate DNS" = @("76.76.19.19", "76.223.122.150")
    "NextDNS" = @("45.90.28.69", "45.90.30.69")
    "AT&T DNS" = @("68.94.156.1", "68.94.157.1")
    "Comcast Xfinity DNS" = @("75.75.75.75", "75.75.76.76")
    "Spectrum DNS" = @("71.10.216.1", "71.10.216.2")
    "CenturyLink DNS (Dynamic IP)" = @("205.171.3.66", "205.171.202.166")
    "CenturyLink DNS (Static IP)" = @("205.171.3.26", "205.171.2.26")
    "Charter Communications DNS" = @("24.196.64.53", "71.10.216.1") 
}

# Loop through each DNS server pair
foreach ($server in $dnsServers.GetEnumerator()) {
    foreach ($dns in $server.Value) {
        Write-Output "Testing DNS server: $($server.Key) with IP: $dns"
        
        # Loop through each domain
        foreach ($domain in $domains) {
            try {
                # Perform the DNS query using the specified server
                $query = Resolve-DnsName -Name $domain -Server $dns -ErrorAction Stop
                
                # If successful, print the IP address(es) resolved
                $query | ForEach-Object {
                    Write-Output "`t$($domain) resolves to: $($_.IPAddress)"
                }
            } catch {
                # If the query fails, print the error message
                 Write-Output "`tFailed to resolve $($domain) using ${dns}: $_"
            }
        }
        Write-Output "--------------------------------------"
    }
}