Basic INN Information

Table of Contents

  1. Welcome to INN 2.4!
  2. What is INN?
  3. Prerequisites
  4. Getting Started
  5. Reporting Bugs
  6. Contributing Code
  7. Mailing Lists
  8. Who's Responsible / Who to Thank
  9. Related Packages
  10. Supporting the INN Effort

Welcome to INN 2.4!

This work is sponsored by Internet Systems Consortium.

Please see INSTALL for installation instructions, NEWS for what's changed from the previous release, and LICENSE for the copyright, license, and distribution terms.

What is INN?

INN (InterNetNews), originally written by Rich Salz, is an extremely flexible and configurable Usenet / netnews news server. For a complete description of the protocols behind Usenet and netnews, see RFC 1036 and RFC 977 (or their replacements). In brief, netnews is a set of protocols for exchanging messages between a decentralized network of news servers. News articles are organized into newsgroups, which are themselves organized into hierarchies. Each individual news server stores locally all articles it has received for a given newsgroup, making access to stored articles extremely fast. Netnews does not require any central server; instead, each news server passes along articles it receives to all of the news servers it peers with, those servers pass the articles along to their peers, and so on, resulting in "flood fill" propagation of news articles.

A news server performs three basic functions: it accepts articles from other servers and stores them on disk, sends articles it has received out to other servers, and offers stored news articles to readers on demand. It additionally has to perform some periodic maintenance tasks, such as deleting older articles to make room for new ones.

Originally, a news server would just store all of the news articles it had received in a file system. Users could then read news by reading the article files on disk (or more commonly using news reading software that did this efficiently). These days, news servers are almost always stand-alone systems and news reading is supported via network connections. A user who wants to read a newsgroup opens that newsgroup in their newsreader software, which opens a network connection to the news server and sends requests for articles and related information. The protocol that a newsreader uses to talk to a news server and that a news server uses to talk to another news server over TCP/IP is called NNTP (Network News Transport Protocol).

INN supports accepting articles via either NNTP connections or via UUCP. innd, the heart of INN, handles NNTP feeding connections directly; UUCP newsfeeds use rnews (included in INN) to hand articles off to innd. Other parts of INN handle feeding articles out to other news servers, most commonly innfeed (for real-time outgoing feeds) or nntpsend and innxmit (used to send batches of news created by innd to a remote site via TCP/IP). INN can also handle outgoing UUCP feeds.

The part of INN that handles connections from newsreaders is nnrpd.

Also included in INN are a wide variety of supporting programs to handle periodic maintenance and recovery from crashes, process special control messages, maintain the list of active newsgroups, and generate and record a staggering variety of statistics and summary information on the usage and performance of the server.

INN also supports an extremely powerful filtering system that allows the server administrator to reject unwanted articles (such as spam and other abuses of Usenet).

INN is free software, supported by Internet Systems Consortium and volunteers around the world. See Supporting the INN Effort below.


Compiling INN requires an ANSI C compiler (gcc is recommended). INN was originally written in K&R C, but supporting pre-ANSI compilers has become enough of a headache that a lot of the newer parts of INN will no longer compile with a non-ANSI compiler. gcc itself will compile with most vendor non-ANSI compilers, however, so if you're stuck with one, installing gcc is highly recommended. Not only will it let you build INN, it will make installing lots of other software much easier. You may also need GNU make (particularly if your system make is BSD-derived), although most SysV make programs should work fine. Compiling INN also currently requires a yacc implementation (bison will do fine).

INN uses GNU autoconf to probe the capabilities of your system, and therefore should compile on nearly any Unix system. It does, however, make extensive use of mmap(), which can cause problems on some older operating systems. See INSTALL for a list of systems it is known to work on. If you encounter problems compiling or running INN, or if you successfully run INN on a platform that isn't listed in INSTALL, please let us know (see Reporting Bugs below).

Perl 5.003 or later is required to build INN. Perl 5.004 is required if you want the embedded Perl filter support (which is highly recommended; some excellent spam filters have been written for INN). Since all versions of Perl previous to 5.004 are buggy (including security problems) and have fewer features, installing Perl 5.004 or later is recommended.

If you want to enable PGP verification of control messages (highly recommended), you will need to have a PGP implementation installed. See INSTALL for more details.

Getting Started

A news server can be a fairly complicated piece of software to set up just because of the wide variety of pieces that have to be configured (who is authorized to read from the server, what newsgroups it carries, and how the articles are stored on disk at a bare minimum, and if the server isn't completely stand-alone -- and very few servers are -- both incoming and outgoing feeds have to be set up and tested). Be prepared to take some time to understand what's going on and how all the pieces fit together. If you have any specific suggestions for documentation, or comments about things that are unclear, please send them to the INN maintainers (see Reporting Bugs below).

See INSTALL for step-by-step instructions for setting up and configuring a news server.

INN also comes with a very complete set of man pages; there is a man page for every configuration file and program that comes with INN. (If you find one that doesn't have a man page, that's a bug. Please do report it.) When trying to figure out some specific problem, reading the man pages for all of the configuration files involved is a very good start.

Reporting Bugs

We're interested in all bug reports. Not just on the programs, but on the documentation too. Please send all such reports to

(patches are certainly welcome, see below). Even if you post to Usenet, please CC the above address. All other INN mail should go to

(please do not send bug reports to this address).

If you have general "how do I do this" questions or problems configuring your server that you don't believe are due to a bug in INN, you should post them to A lot of experienced INN users, including several of the INN maintainers, read that newsgroup regularly. Please don't send general questions to the above addresses; those addresses are specifically for INN, and the INN maintainers usually won't have time to answer general questions.

Contributing Code

If you have a patch or a utility that you'd like to be considered for inclusion into INN, please mail it to

in the body of the message (not as an attachment), or put it on a webpage and send a link. Patches included with a bug report as described above should follow the same procedure, but need not be sent to both addresses (either will do).

Have fun!

Mailing Lists

There are various INN-related mailing lists you can join or send messages to if you like. Some of them you must be a member of before you can send mail to them (thank the spammers for that policy), and one of them is read-only (no postings allowed).

Where announcements about INN are set (only maintainers may post).

Discussion of INN development (postings by members only).

Where to send patches for consideration for inclusion into INN (open posting).

CVS commit messages for INN are sent to this list (only the automated messages are sent here, no regular posting).

Where to send bug reports (open posting). If you're an INN expert and have the time to help out other users, we encourage you to join this mailing list to answer questions. (You may also want to read the newsgroup, which gets a lot of INN-related questions.)

To join these lists, send a subscription request to the -request address. The addresses for the above lists are:

Who's Responsible / Who to Thank

See CONTRIBUTORS for a long list of past contributors as well as people from the inn-workers mailing list who have dedicated a lot of time and effort to getting this new version together. They deserve a big round of applause. They've certainly got our thanks.

This product includes software developed by UUNET Technologies, Inc. and by the University of California, Berkeley and its contributors.

Last, but certainly not least, Rich Salz, the original author of INN deserves a lion's share of the credit for writing INN in the first place and making it the most popular news server software on the planet (no NNTP yet to the moon, but we plan to be there first).

Related Packages

INN users may also be interested in the following software packages that work with INN or are based on it. Please note that none of this software is developed or maintained by ISC; we don't support it and generally can't answer questions about it.


URL: <>

CleanFeed is an extremely powerful spam filter, probably the most widely used spam filter on Usenet currently. It catches excessive multiposting and a host of other things, and is highly configurable. Note that it requires that INN be built with Perl support (the --with-perl option to configure).

GUP (Group Update Program)

URL: <>

GUP provides a way for your peers to update their newsfeeds entries as they want without having to ask you to edit the configuration file all the time. It's useful when feeding peers who take limited and very specific feeds that change periodically.


URL: <>

A PHP-based web news reader that works as a front-end to a regular news server such as INN and lets people read and post without learning a news reader.


URL: <>

PersonalINN is a version of INN modified for personal use and with a friendly GUI built on top of it. It is available for NeXTSTEP or OPENSTEP only, unfortunately.


URL: <>

suck is a separate package for downloading a news feed via a reading connection (rather than via a direct NNTP or UUCP feed) and sending outgoing local posts via POST. It's intended primarily for personal or small-organization news servers who get their news via an ISP and are too small to warrant setting up a regular news feed.

Supporting the INN Effort

Note that INN is supported by Internet Systems Consortium, and although it is free for use and redistribution and incorporation into vendor products and export and anything else you can think of, it costs money to produce. That money comes from ISPs, hardware and software vendors, companies who make extensive use of the software, and generally kind-hearted folk such as yourself.

Internet Systems Consortium has also commissioned a DHCP server implementation and handles the official support/release of BIND. You can learn more about the ISC's goals and accomplishments from the web page at <>.

                                        Russ Allbery
                                        Katsuhiro Kondou
Last modified and spun 2022-12-12