GSAClientDiagnosticsToolkit

1.0.0-beta1

Private/Test-IPorFQDN.ps1

#
# Function: Test-IPorFQDN
# Determines whether a string is a valid IPv4 address or a valid FQDN.
# Example: Test-IPorFQDN -FQDNorIP 'fileserver.contoso.com' # returns 'FQDN'
#
function Test-IPorFQDN
{
    param (
        [string]$FQDNorIP
    )

    # Define regular expressions for matching IPv4 addresses and FQDNs.
    $ipRegex = '^(([0-9]{1,3}\.){3}[0-9]{1,3})$'
    $fqdnRegex = '^([a-zA-Z0-9]+(-[a-zA-Z0-9]+)*\.)+[a-zA-Z]{2,}$'

    # Check if the input string matches the IPv4 address pattern.
    if ($FQDNorIP -match $ipRegex)
    {
        foreach ($octet in ($FQDNorIP -split '\.'))
        {
            if ([int]$octet -lt 0 -or [int]$octet -gt 255)
            {
                return $null
            }
        }
        return 'IP'
    }

    # Check if the input string matches the FQDN pattern.
    if ($FQDNorIP -match $fqdnRegex)
    {
        return 'FQDN'
    }

    return $null
}