NNTP

NNTP, or Network News Transfer Protocol, is an Internet application layer protocol used for the distribution, retrieval, and posting of Usenet articles. It operates as a simple request-response protocol over TCP between a client and a server. Clients connect to an NNTP server to browse groups, fetch headers or full articles, and submit new postings.

A typical session begins by selecting a newsgroup with GROUP, then listing articles with STAT, HEAD, and ARTICLE. Clients can fetch by article number or Message-ID. The protocol supports commands to read active newsgroups, recent posts, and to post new articles. Articles are stored as plain text with headers and body, and servers may store duplicates across a network of servers. Multi-line responses are terminated by a single line containing only a dot, and lines starting with a dot are dot-stuffed.

Security: originally unencrypted; later NNTP over TLS (port 563) or STARTTLS on port 119 is used to secure connections. Many servers support authentication via AUTHINFO USER/PASS to enable posting and moderation.

Structure: Usenet is organized into hierarchies of newsgroups; groups may be moderated; articles propagate between servers through feed protocols. From a user perspective, Usenet provides asynchronous threaded discussions; retention periods vary by server.

History and status: NNTP emerged in the 1980s to support Usenet. It remains in use on some servers and by various newsreaders, though its popularity has declined with the rise of web forums and streaming platforms.