Usenet News HOWTO Shuvam Misra (usenet at starcomsoftware dot com) Revision History Revision 2.1 2002−08−20 Revised by: sm New sections on Security and Software History, lots of other small additions and cleanup Revision 2.0 2002−07−30 Revised by: sm Rewritten by new authors at Starcom Software Revision 1.4 1995−11−29 Revised by: vs Original document; authored by Vince Skahan. Usenet News HOWTO Table of Contents 1. What is the Usenet?........................................................................................................................................1 1.1. Discussion groups.............................................................................................................................1 1.2. How it works, loosely speaking........................................................................................................1 1.3. About sizes, volumes, and so on.......................................................................................................2 2. Principles of Operation...................................................................................................................................4 2.1. Newsgroups and articles...................................................................................................................4 2.2. Of readers and servers.......................................................................................................................6 2.3. Newsfeeds.........................................................................................................................................6 2.3.1. Fundamental concepts.............................................................................................................6 2.3.2. Types of newsfeeds.................................................................................................................8 2.4. Control messages............................................................................................................................10 3. Usenet news software....................................................................................................................................13 3.1. A brief history of Usenet systems...................................................................................................13 3.2. C−News and NNTPd......................................................................................................................13 3.3. INN.................................................................................................................................................14 3.4. Leafnode.........................................................................................................................................14 3.5. Suck................................................................................................................................................15 3.6. Carrier class software......................................................................................................................15 4. Setting up CNews + NNTPd.........................................................................................................................17 4.1. Getting the sources and stuff...........................................................................................................17 4.1.1. The sources............................................................................................................................17 4.1.2. The key configuration files....................................................................................................18 4.2. Compiling and installing.................................................................................................................18 4.3. Configuring the system: What and how to configure files?...........................................................19 4.4. Testing the system..........................................................................................................................22 4.5. pgpverify and controlperms............................................................................................................22 4.6. Feeding off an upstream neighbour................................................................................................23 4.7. Configuring outgoing feeds............................................................................................................23 4.7.1. By UUCP...............................................................................................................................23 4.7.2. By NNTP...............................................................................................................................24 5. Setting up INN...............................................................................................................................................25 5.1. Getting the source...........................................................................................................................25 5.2. Compiling and installing.................................................................................................................25 5.3. Configuring the system...................................................................................................................25 5.4. Setting up pgpverify........................................................................................................................25 5.5. Feeding off an upstream neighbour................................................................................................25 5.6. Setting up outgoing feeds...............................................................................................................25 5.7. Efficiency issues and advantages....................................................................................................25 6. Connecting email with Usenet news............................................................................................................26 6.1. Feeding Usenet news to email........................................................................................................26 6.2. Feeding email to news: the mail2news gateway.............................................................................26 6.3. Using GNU Mailman as an email−NNTP gateway........................................................................27 6.3.1. GNU's all−singing all−dancing MLM...................................................................................27 i Usenet News HOWTO Table of Contents 6. Connecting email with Usenet news 6.3.2. Features of GNU Mailman.............................................................................................27 6.3.3. Gateway features connecting NNTP and email....................................................................27 7. Security issues................................................................................................................................................28 7.1. Intrusion threats..............................................................................................................................28 7.1.1. Generic server vulnerabilities................................................................................................28 7.1.2. Vulnerabilities in Usenet software........................................................................................29 7.2. Vulnerabilities unique to the Usenet service..................................................................................29 7.2.1. Unsolicited commercial messages.........................................................................................30 7.2.2. Spurious control messages....................................................................................................30 8. Access control in NNTPd..............................................................................................................................31 8.1. Host−based access control..............................................................................................................31 8.2. User authentication and authorisation.............................................................................................31 8.2.1. The NNTPd password file.....................................................................................................31 8.2.2. Mapping users to newsgroups...............................................................................................31 8.2.3. The X−Authenticated−Author article header........................................................................31 8.2.4. Other article header additions................................................................................................31 9. Components of a running system................................................................................................................32 9.1. /var/lib/news: the CNews control area............................................................................................32 9.2. /var/spool/news: the article repository............................................................................................33 9.3. /usr/lib/newsbin: the executables....................................................................................................33 9.4. crontab and cron jobs......................................................................................................................33