title: What is a valid ip range?
body: <p>The azure terraform resource manager has a field <a href="https://www.terraform.io/docs/providers/azurerm/r/network_security_rule.html#source_address_prefix" rel="nofollow noreferrer"><code>source_address_prefix</code></a>:</p>
  
  <blockquote>
    <p>CIDR or source <strong>IP range</strong> or * to match any IP. Tags such as
    ‘VirtualNetwork’, ‘AzureLoadBalancer’ and ‘Internet’ can also be used.
    This is required if source_address_prefixes is not specified.</p>
  </blockquote>
  
  <p>What is a valid IP range in this context?</p>