Wasn't sure where to post this, hope this will suffice -- sorry if the wording is simple, I've never done anything like this before.
I've set up a WordPress server with Microsoft WebMatrix on a VM running Server 2012. I have it working on our network (via http://servername/ to the point that I'm ready to open it for public viewing.
I've been given an external IP address which points to the internal IP address of the server. Our domain is registered with 123-reg, so I've added in a type A DNS entry for "blog" (for blog.ourdomain.org) pointing to the external address.
I assume I need to change the URL the WordPress installation recognises itself as being at, however currently there's not even a response to a ping of the external IP address, and visiting blog.ourdomain.org directs to 123-reg.co.uk -- Am I missing a step? (Pinging blog.ourdomain.org attempts to ping the correct IP address, so presumably the DNS entry is working).
Help would be hugely appreciated.