A protocol defines the method of exchanging data over the network. Each protocol has its own set of rules and specifies the interactions between the communicating entities. One of the most common and known protocols is HTTP (HyperText Transfer Protocol), which is a protocol used to transmit data over the world wide web (Internet).
NNTP – Network News Transfer Protocol
The Network News Transfer Protocol is an application layer protocol. It is used for transporting Usenet news articles (Netnews) between news servers and for reading and posting articles by end user client applications. RFC 977 is the specification for the Network News Transfer Protocol founded in March 1986.
NNTP manages the notes posted on Unset newsgroup which is a collection of posted notes on a subject posted by different users. It uses a reserve port number 119. These servers are responsible to manage the Usenet newsgroup collected globally.
Usenet was originally designed based on the UUCP network, with most article transfers taking place over direct point-to-point telephone links between news servers, which were powerful timesharing systems. Readers have logged into these computers for reading the articles directly from the local disk.
As distributed file systems were not yet widely available, a new protocol was developed based on the client-server model. The newly developed protocol resembled the Simple Mail Transfer Protocol (SMTP) for exchanging newsgroup articles. An NNTP client is included as a part of Opera, Internet Explorer, Netscape or you may use a separate client program called a newsreader.
A newsreader, also known as a news client, is an application software that reads articles on Usenet (generally known as newsgroup), either directly from the news server’s disks or via the NNTP. The well-known TCP port 119 is reserved for NNTP. TCP port 563 is used for connecting to a news server with Transport Layer Security (TLS). This is sometimes referred to as NNTPS.