Static ip address

Three problems, first, Cox doesn't offer static ip's to residential accounts.  Second, running a server on a residential account is against their TOS.  From Cox's Acceptable use Policy: "You may not operate, or allow others to operate, servers of any type or any other device, equipment, and/or software providing server-like functionality in connection with the Service, unless expressly authorized by Cox."  Third, Cox blocks inbound port 80.

If you upgrade to a business class account, it is possible.  Using DDNS is a work-a-round for a static IP.  Using a port other than 80 works around the port block but anyone accessing your server would have to know the port.  There is no getting around the TOS, setting up a server violates it.