Leafnode FAQ

Dr. Cornelius Krasel

Matthias Andree

$Id: FAQ.xml,v 1.12 2002/11/10 20:21:22 emma Exp $

$Date: 2002/11/10 20:21:22 $


Table of Contents

Leafnode frequently asked questions, with answers.
Installation problems
Configuration problems
Problems at run time
Problems with particular newsreaders
License issues
Obtaining a stack backtrace
From a core file.
Running a program under gdb supervision.
From a running/hanging leafnode

Google

program.
Red Hat and the inetd vs. xinetd issue.

Leafnode frequently asked questions, with answers.

Installation problems

Q:. Leafnode does not compile on my system.
Q:.

Leafnode does not compile on my system.

A:.

Apple MacOS X/Darwin.Apple introduced Two-Level Namespace Executables with MacOS X 10.1. This change affects how the linker works, and the linker itself is driven by the libtool parts that ship with PCRE. libtool as of that version and up to version 1.4.2 does not yet support the new linker semantics of MacOS X 10.1, and the compile broke up to and including leafnode 1.9.27.

Since leafnode 1.9.28, the embedded pcre/ directory contains two changes to overcome these problems:

  1. the embedded libtool parts in configureare patched to detect these new MacOS versions and pass appropriate options to the linker.

  2. When leafnode uses the embedded libtool, it passes the --disable-shared option to PCRE's configure, which avoids this trouble with shared libraries and speeds up the build -- leafnode will links statically anyhow to avoid the PCRE installation. The file configure.gnu does that, and it will not get applied if you explicitly configure pcre/.

So, effectively, an update to leafnode 1.9.28 should fix this problem. If it does not, contact the leafnode mailing list.

Linux.Another common reason for the build to fail is that Leafnode depends on some system-specific information which is usually included in the sources of the kernel.

Unfortunately, some Linux distribution do not install kernel sources by default; therefore, compilation of Leafnode (and most other programs as well) will fail. The obvious solution is to install the kernel sources. On Linux, if the kernel sources are installed in /usr/src/linux-a.b.cc (with a.b.cc being the version number of your kernel), create a symlink to /usr/src/linux.

Configuration problems

Q:. Leafnode refuses to start and tells things about my hostname!
Q:. Does leafnode support local newsgroups?
Q:. How do I use fetchnews with NNTP/SSL servers, such as nntp.sourceforge.net?
Q:.

Leafnode refuses to start and tells things about my hostname!

A:.

There is a separate documentation file dedicated to this issue, how to obtain a hostname, and how to tell leafnode about it. Please see README-FQDN or README-FQDN.html for details.

Q:.

Does leafnode support local newsgroups?

A:.

Leafnode 1.x does not support local newsgroups. Leafnode 2.x will do that.

Q:.

How do I use fetchnews with NNTP/SSL servers, such as nntp.sourceforge.net?

A:.

Warning: SourceForge does not currently support the HEAD, STAT and BODY commands, so leafnode-1 is totally out of the play for now. leafnode-2 will work for lurking, but will likely be unable to post. Sourceforge are aware that we need these commands and will add them at a later time.

  1. Obtain stunnel and install it.

  2. Arrange for stunnel to be started at system boot time, try:

    /usr/sbin/stunnel -c -d 127.0.0.1:563 -r nntp.sourceforge.net:563

    Add

    server = localhost
    port = 563
    username = YOUR_SF_LOGIN
    password = TOP_SECRET
    

    to your /etc/leafnode/config.

Problems at run time

Q:. I cannot post, leafnode tells me the Message-ID is invalid.
Q:. I cannot connect to my newsserver.
Q:. Remote users cannot connect to leafnode.
Q:. Fetchnews does not fetch any articles.
Q:. Fetchnews has problems retrieving new newsgroups.
Q:. Since the update, fetchnews does not post any of my old articles!
Q:. Since the update, fetchnews does not post my new articles!
Q:. While fetchnews is running, my modem hangs up.
Q:. How can I run fetchnews as regular user (not root)?
Q:. I have unsubscribed from a newsgroup, but fetchnews still pulls articles for that group.
Q:. Texpire does not expire articles.
Q:. How do I stop fetchnews from unsubscribing from newsgroups?
Q:.

I cannot post, leafnode tells me the Message-ID is invalid.

A:.

Netscape Communicator, Mozilla and derived products (Beonex) will by default generate the Message-ID from the domain part of your E-Mail address. However, if your address is that of a big freemailer site (hotmail.com, yahoo.com, gmx.de), this will lead to invalid Message-IDs.

To work around this, go to the Mail & Newsgroups settings and enclose your E-Mail addresses into double quote marks, like this:"matthias.andree@gmx.de"This will prevent your Netscape-based newsreader from generating the invalid Message-ID and leave the generation to leafnode.

Q:.

I cannot connect to my newsserver.

A:.

You may not have configured inetd or xinetd properly, or the corresponding super server is not running. Please review the installation instructions. See below for information specific to Red Hat.

To test the setup, try: telnet localhost 119. Leafnode should then reply with (on one line):

200 Leafnode NNTP Daemon, version 1.9.27.rel running at merlin.emma.line.org
(my fqdn: merlin.emma.line.org)

Q:.

Remote users cannot connect to leafnode.

A:.

You are connecting from outside the same networks that your leafnode server is in. Leafnode by default refuses connections from outside your LAN to prevent your leafnode server from abuse should you forget to configure tcpd or make a mistake when writing your hosts.allow or hosts.deny files. Please see /etc/leafnode/config.example for the allowstrangers option and how to configure this option. You will have to change the capitalization and write a special number on that line as you put it into your /etc/leafnode/config.

Q:.

Fetchnews does not fetch any articles.

A:.
  • You did not read any pseudo articles with your news reader. Subscribe to some groups, enter them and read the leafnode placeholder article.

  • Your groupinfo file may be corrupt. Run fetchnews -f.

  • /var/spool/news may have wrong permissions. /var/spool/news and all its subdirectories should be owned by user and group news and have permissions drwxrwsr-x (02755).

Q:.

Fetchnews has problems retrieving new newsgroups.

A:.

Maybe your upstream server supports neither the XGTITLE news.group.name nor the LIST NEWSGROUPS news.group.name command.

In this case, add nodesc = 1 to the server entry in /etc/leafnode/config, as described in the leafnode(8) manual page and the /etc/leafnode/config.example file.

Q:.

Since the update, fetchnews does not post any of my old articles!

A:.

Go read the "incompatible changes" and "updating" sections in NEWS and README.

Q:.

Since the update, fetchnews does not post my new articles!

A:.

You have probably mixed old and new binaries. Check your inetd.conf or xinetd.conf configuration if they really point to the new binary.

Q:.

While fetchnews is running, my modem hangs up.

A:.

An article that causes the interruption may contain three plus signs in a row (“+++”), which many modems interpret as the beginning of a command. You can change or disable this “escape” sequence. Consult your modem's manual, register S2 is a common place to configure this.

Q:.

How can I run fetchnews as regular user (not root)?

A:.

For security reasons, this is not possible.

However, there is a tool named “sudo” that allows a regular, unprivileged user to impersonate another user, and this can be used to enable a regular user to run fetchnews.

“sudo” is available from http://www.courtesan.com/sudo/.

If “sudo” is installed on your system, then run visudo as root and add this line:

username ALL = (news) NOPASSWD: /path/to/fetchnews

Remember to replace “username” and “/path/to/” with the user's login and the proper path to fetchnews.

Now, the user who has been enabled access to fetchnews can just type sudo -u news /path/to/fetchnews to run fetchnews.

Q:.

I have unsubscribed from a newsgroup, but fetchnews still pulls articles for that group.

A:.

Your news reader talks to leafnode via the NNTP protocol. This protocol provides no means for Leafnode to determine which newsgroups you are actually subscribe. Therefore, Leafnode assumes that a newsgroup that is not read for a certain time (which can be configured with the timeout_long parameter) is unsubscribed and will only stop retrieving articles in it after this time.

If you are impatient and want to stop retrieving articles from that group immediately, delete the corresponding file in the /var/spool/news/interesting.groups/ directory. The articles that are already in your spool are still subject to the regular texpire schedule, however.

Q:.

Texpire does not expire articles.

A:.

The backup software that you are using may not reset the atime after reading a file. Check if you can reconfigure it to reset the “atime”.

As a workaround, run texpire -f. This will expire articles somewhat earlier because expiry is then determined from the time the file was last modified, rather than when it was last accessed.

Q:.

How do I stop fetchnews from unsubscribing from newsgroups?

A:.

Run fetchnews -n rather than just fetchnews.

Problems with particular newsreaders

Q:. When searching news with Netscape, I only get back unknown command.
Q:. Outlook Express locks up.
Q:. Tin complains about a missing file /var/lib/news/active.
Q:.

When searching news with Netscape, I only get back “unknown command”.

A:.

To search news, older versions of Netscape needed a news server which supports the XPAT command. Leafnode-1 does not. If you want to use Netscape, you have to upgrade to version 4.5 and press the “options” button which appears in the “search messages” window. In the box which appears you have to select “on your local system”.

Q:.

Outlook Express locks up.

A:.

This can be caused by a corrupted inbox file in Outlook Express. It is said to happen during the initial install of Internet Explorer. To fix this problem, go to “Add/Remove Programs”, choose “Internet Explorer”, then “Repair installation.”

Thanks to Jim Gifford who talked to Microsoft to find this solution.

Q:.

Tin complains about a missing file /var/lib/news/active.

A:.

Either you have started the wrong version of tin (the one which tries to read news directly from the spool) or your groupinfo file is corrupt.

In the first case, simply invoke tin with the -r flag: tin -r. If this does not help, try to rebuild the groupinfo file by running fetchnews -f.

License issues

Q:. Why is Leafnode not licensed under the GPL?
Q:.

Why is Leafnode not licensed under the GPL?

A:.

There are several reasons:

  • Originally, Arnt Gulbrandsen licensed Leafnode under his own license:

    Use, modification and distribution is allowed without limitation, warranty, or liability of any kind.

    This license is very broad. The same spirit is (in my opinion) contained in the X11 license, which is used by Leafnode nowadays.

  • I (Cornelius) do not like the philosophy of the FSF. They seem to emphasize that every project they conceived is good whereas everything else is bad. If they cannot argue the software away this way, they claim it to be part of the project, such as calling Linux "GNU/Linux". Or, as Arnt Gulbrandsen put it:

    Freedom includes the freedom to disagree with me and still use my software.

Obtaining a stack backtrace

This section will tell you how to obtain a stack backtrace, a special program state output that is very useful to somebody who is about to debug a crash.

The prerequisite to work is that the program is not stripped, i. e. it contains the debug symbols. That means leafnode must have been installed with make install rather than make install-strip. Note that most packagers (for RPM at least) use make install-strip to save space.

To find out if your leafnode installation has been stripped, type file /usr/local/sbin/leafnode (adjust the path as necessary, packages will usually install to /usr/sbin/leafnode instead), here is a sample output of an unstripped program:

$ file /usr/local/sbin/leafnode
/usr/local/sbin/leafnode: ELF 32-bit LSB executable, Intel 80386, version 1,
dynamically linked (uses shared libs), not stripped

From a core file.

This is simple:

  1. Type gdb PROGRAM core. Replace PROGRAM by the name of the program that crashed, for example fetchnews.

  2. Type backtrace full.

  3. Type quit.

Running a program under gdb supervision.

  1. Type gdb PROGRAM. Replace PROGRAM by the name of the program that crashes, for example fetchnews. Do not give any program options, gdb does not understand them here.

  2. Type run OPTIONS, where you name the options that you would normally pass to the program itself. Just a plain run is also fine.

  3. Wait until the program crashes. The output might look like similar to this:

    
    This GDB was configured as "i686-pc-linux-gnu"...
    (gdb) run -vvn
    
    Starting program: /tmp/crashme
    
    Program received signal SIGSEGV, Segmentation fault.
    main () at crashme.c:4
    4           *x = 4;
    (gdb)
    
  4. Type backtrace full, this is the desired stack backtrace.

  5. Type quit to leave gdb.

From a running/hanging leafnode program.

  1. Find out the Process ID of the hanging leafnode program. Type ps axw | grep PROGRAM | grep -v grep on BSD systems and Linux, replacing PROGRAM by the name of the program. Use ps -ef instead on SysV systems such as Solaris.

    You will get an output like:

     1995 ?  S      0:00 /usr/local/sbin/leafnode
    			

    1995 is the Process ID.

  2. Then attach gdb: gdb PROGRAM 12345, replacing PROGRAM by the program's name and 12345 by the PID that you have just found out.

  3. Type backtrace full.

  4. Type detach.

  5. Type quit.

Red Hat and the inetd vs. xinetd issue.

William Hooper

RedHat Linux has changed stance on inetd/xinetd over the years. In the 6.x version, inetd was used, while xinetd is used in the 7.x series and 8.0. Note in the following I make the assumption that the "Gnome workstation" and "KDE workstation" installs are the same in regard to our discussion. Also, when in doubt a simple rpm -qa | grep inetd will show you if either inetd or xinetd is installed. The service and chkconfig commands can be used to be sure [x]inetd is running and configured to run at boot time. By default, runlevels 3, 4, and 5 start [x]inetd.

Beginning with Redhat 6.2, inetd was broken out as a separate RPM and not included when doing a "Workstation" install. This stands true for the 7.x series (xinetd not installed) until 7.3. In Redhat 7.3, xinetd was added back to the "Workstation" install as a dependency for "sgi_fam". Note, this change is not reflected in the RH documentation, which states that xinetd is not installed in "Workstation" installs.

In Redhat 8.0, the install options have changed, now offering a "Personal Desktop" install. When doing a "Workstation" or "Personal Desktop" install xinetd is installed as in 7.3, presumably to satisfy the same dependency.

In cases where inetd is not installed, no other RPMs are required to install it. This means to install it you have three options (for RedHat 6.2 substitute inetd instead of xinetd):

  1. Best - If you have registered for Redhat's up2date service, just type "up2date xinetd" as root.

  2. Next Best - Install RPM from updates.redhat.com (version numbers current as of 2002-11-10 for RH 7.3). You can manually download the RPM and install it (as root) using rpm -ivh xinetd-2.3.9-0.73.i386.rpm, or have RPM download it for you by using (again, as root) rpm -ivh http://updates.redhat.com/7.3/en/os/i386/xinetd-2.3.9-0.73.i386.rpm

  3. Worse - Install the RPM from the original CD. This is usually the worse option because the updates (used above) are released to fix security issues.

    (All as root) First mount the first RH CD by putting it in the CD-ROM and doing a mount /mnt/cdrom, and install the RPM similar to this: cd /mnt/cdrom/Redhat/RPMS/xinetd-2.3.7-2.i386.rpm.