Question : Unable to receive emails from outside network

No one is able to recieve emails from outside the network.   No new changes have been made.  We are currently running Outlook 2007, exchange server

Answer : Unable to receive emails from outside network

Make sure that you MX record is pointing to the correct IP address still and the port 25 is still open to the exchange server(if you have a spam filter in front of it make sure that port 25 is open to that.). Also try telneting in to your public IP address on port 25 and see if the smtp server responds. You can also try restarting the SMTP server.