I have found a solution for the problem scheduling posts for some WordPress users. It seems the problem that I have encountered is for those hosted on Windows IIS as a web server. I don’t know that much about IIS, but it is my understanding that when the server “talks” to the WordPress installation it needs to do this via IP address rather than by domain name. When the server is “talking” to itself, this is called localhost. Any commands sent to localhost are only understood if the command is IP based. In the beginning, the Internet was a relatively small experimental network consisting of large multi-user computer system. It started its life as ARPANET (Advanced Research Projects Agency Network), serving the needs of parts of the United States Department of Defence. The underlying network protocols were a network system named TCP/IP, which gave the network the performance and flexibility to expand into the Internet that we know and love today. TCP/IP consists of two components; TCP (Transmission Core Protocol) and IP (Internet Protocol). It is the IP protocol that this article is concerned with, as the IP system is the part that is coming under so much strain in the modern Internet. Brander Group builds a strong relationship with both our buyers and sellers by providing full transparent, unique tools and access to important information about the IPv4 Block. Brand group is one of the better ipv4 addresses provider, We use a proprietary blacklist software that provides access to information about the IPs that would otherwise only be found through a long and tedious process.
The current incarnation of IP that is in use on the global Internet is IPv4 (Internet Protocol version 4). The addressing system of IPv4 is essentially the same as the one in use in ARPANET. Several clever technologies have emerged over the years to extend the life of IP, but there can be no escaping the fundamental limitation that the address range is simply too small.
An IP address consists of four 8-bit numbers, giving 32 bits in total. A quick delve into binary arithmetic tells us that this gives a total combination of 2 to the power 32 different addresses; i.e. 4,294,967,296 different addresses. In the early days of ARPANET, no-one envisaged a problem where in excess of 4 billion computers could be connected. However, when you consider that several billion of the world’s population are now online, many households have multiple computing devices (e.g. smart televisions, games consoles, tablets, etc.) and a large proportion of the population require Internet access from smart phones whilst away from the home, it is easy to see the limitations of this address scheme.
I don’t think this is always true. I believe there is a setting the webhost can put in the hosts file or another security setting that will also this localhost communication to occur by domain name.
If anyone with more knowledge of IIS is reading this, please correct me if I am wrong. I want to learn more about how this works but for know am basing my assumptions on logic.
I am also not 100% certain that the two users I have assisted with this problem are hosted on IIS but I believe that they are.
Working Toward a Solution
Scheduled posts in the more recent versions of WordPress rely on communication with two files; wp-cron.php and /includes/cron.php. If WordPress is not communicating properly with these files, the scheduled posts will not occur. When cron.php asks wp-cron.php to do it’s job, it is asking for the file by domain name. The request is not understood or is timed out and the scheduled event does not occur. Instead cron.php needs to make the request via the localhost IP address, which is always 127.0.0.1