title: Recaptcha IP addresses
body: <p>Okay, so we implement Recaptcha in production.  We get errors because it can't reach the IP address it needs to use the service.  We open a port for the IP address to reach Google.  No problem.  We do that and configure that IP address explicitly to work.  It works great.  Then, the next day, we start getting errors again because Recaptcha is using a <em>different</em> IP address.  I can allow requests from that IP address, too, but now I'm unsettled.  Where are these addresses coming from?  How do I configure this to work reliably?</p>