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<!ENTITY xinetd "<application>xinetd</application>">
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<articleinfo>
<author><honorific>Dr</honorific><firstname>Cornelius</firstname><surname>Krasel</surname></author>
<author><firstname>Matthias</firstname><surname>Andree</surname> </author>
<title>Leafnode FAQ</title>
<copyright>
<year>2002</year>
<holder>Cornelius Krasel</holder>
</copyright>
<copyright>
<year>2002</year>
<year>2003</year>
<year>2004</year>
<year>2005</year>
<year>2006</year>
<year>2009</year>
<holder>Matthias Andree</holder>
</copyright>
<pubdate role="rcs">$Date: 2006/04/09 17:19:32 $</pubdate>
<!-- releaseinfo>$Id: FAQ.xml,v 1.17 2004/09/03 21:14:46 emma
Exp $</releaseinfo -->
</articleinfo>
<sect1 id="FAQ"><title>Leafnode frequently asked questions, with answers.</title>
<sect2><title>Installation-related problems, including relocations</title>
<qandaset defaultlabel='qanda'>
<qandaentry>
<question><para>Compiling causes a message
'SA_RESETHAND undeclared'!</para></question>
<answer>
<para>This means that your operating system is too old and
lacks this symbol which is required by POSIX.
Please update your operating system. </para>
</answer>
</qandaentry>
<qandaentry>
<question><para>I cannot compile leafnode on Linux!</para></question>
<answer>
<para>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.</para>
<para>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
<filename>/usr/src/linux-a.b.cc</filename> (with a.b.cc being the version
number of your kernel), create a symlink to
<filename>/usr/src/linux</filename>.</para>
</answer>
</qandaentry>
<qandaentry>
<question><para>Where/how do I get the source RPM? I
want to modify it.</para></question>
<answer><para>You can generate it yourself from the
source tarball (which contains the necessary
<filename>.spec</filename> file. Just
type:
<userinput>rpmbuild -ts leafnode-1.11.5.tar.bz2</userinput> – of
course, you will have to adjust the version
shown here. For RPM 3.x and older, type this instead:
<userinput>rpm -ts leafnode-1.11.5.tar.bz2</userinput>
</para>
</answer>
</qandaentry>
<qandaentry>
<question><para>How do I copy/move the spool?</para></question>
<answer><para>There are two important requirements to heed:</para>
<orderedlist><listitem><para>You must copy hard links as hard links. There are three supported methods to achieve that. In each of the following examples, replace the source and DEST directories:</para>
<itemizedlist><listitem><para>On POSIX compliant systems, use <userinput>mkdir DEST && sudo pax -r -w -p e -H /var/spool/news/ DEST</userinput></para></listitem>
<listitem><para>If rsync is installed, use (note the trailing slash!), use <userinput>rsync -aH /var/spool/news/ DEST</userinput></para></listitem>
<listitem><para>If GNU cp is installed (it's sometimes called gcp), use <userinput>cp -a /var/spool/news/ DEST</userinput></para></listitem></itemizedlist>
<para>If you fail to do this, texpire may expire articles too early. You can repair broken hard links with <userinput>texpire -r</userinput>.</para>
</listitem>
<listitem><para>You must update the hashed message.id/nnn/ links if you are running leafnode from the new location. Unless the new spool directory has the same name as the old one (if, for instance, moving to a new computer), run <userinput>texpire -r</userinput> before any other leafnode program. Leafnode-1's spool layout unfortunately depends on the name of the spool directory, and when that changes, files may have to be moved between the message.id/nnn/ directories, and <userinput>texpire -r</userinput> does just that - and it also repairs hard links.</para>
<para>If you fail to do this, leafnode may not find articles in its spool.</para></listitem></orderedlist>
</answer>
</qandaentry>
</qandaset>
</sect2>
<sect2><title>Configuration problems</title>
<qandaset defaultlabel='qanda'>
<qandaentry><question><para>Leafnode refuses to start and tells
things about my hostname!</para></question>
<answer><para>There is a separate documentation file dedicated
to this issue, how to obtain a hostname, and how to tell
leafnode about it. Please see
<filename>README-FQDN</filename> or
<filename>README-FQDN.html</filename> for details.</para></answer></qandaentry>
<qandaentry><question><para>Does leafnode support local
newsgroups?</para></question>
<answer><para>Leafnode 1.x does not support local newsgroups.
Leafnode 2.x will do that.</para></answer>
</qandaentry>
<qandaentry id='nntpds'>
<question><para>How do I run leafnode as NNTP+SSL
server?</para></question>
<answer><para>Wrap leafnode with an SSL wrapper:</para>
<orderedlist><listitem><para>
Obtain <ulink
url='http://stunnel.mirt.net'>stunnel
version 3</ulink>
and install it.
</para></listitem>
<listitem><para>Create a certificate and
save it to
<filename>/etc/leafnode/stunnel.pem</filename>, see
the stunnel documentation.
Implications such as whether to
use signed certificates are beyond the
scope of this document.</para></listitem>
<listitem><para>Add a configuration to your
inetd.conf, xinetd.conf or spawn a new
tcpserver process as described in the
<filename>INSTALL</filename> document; but instead of
<userinput>/usr/local/sbin/leafnode</userinput>,
you'll type</para><para>
<userinput>/usr/local/sbin/stunnel -f -p
/etc/leafnode/stunnel.pem -l
/usr/local/sbin/leafnode.</userinput></para></listitem></orderedlist></answer></qandaentry>
<qandaentry id='nntps'>
<question><para>How do I use fetchnews with NNTP/SSL
servers, such as
<filename>nntp.sourceforge.net</filename>?</para></question>
<answer><para>Warning: SourceForge does not
currently support the
<command>HEAD</command>,
<command>STAT</command> and
<command>BODY</command> 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.</para>
<orderedlist><listitem><para>
Obtain <ulink
url='http://stunnel.mirt.net'>stunnel
version 3</ulink>
and install it.
</para></listitem>
<listitem><para>Arrange for stunnel to be started at
system boot time, try:</para>
<para><userinput>/usr/sbin/stunnel -c -d
127.0.0.1:563 -r
nntp.sourceforge.net:563</userinput></para>
<para>Add</para>
<para><programlisting>server = localhost
port = 563
username = YOUR_SF_LOGIN
password = TOP_SECRET
</programlisting></para>
<para>to your
<filename>/etc/leafnode/config</filename>.
</para></listitem>
</orderedlist></answer>
</qandaentry>
</qandaset>
</sect2>
<sect2><title>Problems at run time</title>
<sect3><title>leafnode (the NNTP server)</title>
<qandaset defaultlabel='qanda'>
<qandaentry><question><para>I cannot post, leafnode tells me the
Message-ID is invalid.</para></question>
<answer><para>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.</para>
<para>To work around this, go to the <command>Mail &
Newsgroups</command> settings and enclose your E-Mail
addresses into double quote marks, like
this:<userinput>"matthias.andree@gmx.de"</userinput>This
will prevent your Netscape-based newsreader from generating
the invalid Message-ID and leave the generation to leafnode.</para></answer></qandaentry>
<qandaentry>
<question><para>I cannot connect to my newsserver.</para></question>
<answer><para>You may not have configured &inetd; or
&xinetd; properly,
or the corresponding super server is not running. Please review
the installation instructions. <link
linkend="redhat-xinetd">See below for
information specific to Red Hat.</link></para>
<para>
To test the setup, try: <userinput>telnet localhost
119</userinput>. Leafnode should then
reply with (on one line):
<screen>200 Leafnode NNTP Daemon, version 1.9.27.rel running at merlin.emma.line.org
(my fqdn: merlin.emma.line.org)</screen>
</para>
</answer>
</qandaentry>
<qandaentry>
<question><para>Remote users cannot connect to leafnode.</para></question>
<answer><para>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
<filename>hosts.allow</filename> or
<filename>hosts.deny</filename> files.
Please see <filename>/etc/leafnode/config.example</filename> for the
<parameter>allowstrangers</parameter> option and how to
configure this option, and its requirements.
YOU are responsible for the abuse of your
server if this option is enabled, so only
give access to people with static IP whom
you trust.</para><para>If the clients are on
dynamic IP, please use other methods of
access instead, for instance SSH tunnels
(which are also available on Windows, before
you ask).</para></answer>
</qandaentry>
</qandaset>
</sect3>
<sect3><title>fetchnews</title>
<qandaset>
<qandaentry>
<question>
<para>Fetchnews does not fetch any articles.</para>
</question>
<answer><para>There are several reasons why this may
be the case:</para><itemizedlist>
<listitem><para>You did not read any pseudo articles with
your news reader. Subscribe to some groups,
enter them and read the leafnode placeholder
article.</para></listitem>
<listitem><para>Your groupinfo file may be corrupt.
Run <userinput>fetchnews
-f</userinput>.</para></listitem>
<listitem><para><filename>/var/spool/news</filename> may have
wrong permissions.
<filename>/var/spool/news</filename> and all its
subdirectories should be owned by user and
group news and have permissions drwxrwsr-x
(02755).</para></listitem>
</itemizedlist></answer>
</qandaentry>
<qandaentry>
<question><para>Fetchnews has problems
retrieving new newsgroups.</para></question>
<answer><para>Maybe your upstream server supports neither the
<command>XGTITLE news.group.name</command> nor the
<command>LIST NEWSGROUPS news.group.name</command>
command.</para>
<para>In this case, add <userinput>nodesc =
1</userinput> to the
server entry in <filename>/etc/leafnode/config</filename>,
as described in the
<citerefentry><refentrytitle>leafnode</refentrytitle><manvolnum>8</manvolnum></citerefentry>
manual page and the
<filename>/etc/leafnode/config.example</filename> file.</para>
</answer>
</qandaentry>
<qandaentry><question><para>Since the update, fetchnews does
not post my new articles!</para></question>
<answer><para>You have probably mixed old and new
binaries. Check your
<filename>inetd.conf</filename> or
<filename>xinetd.conf</filename> configuration
if they really point to the new binary.</para></answer></qandaentry>
<qandaentry>
<question>
<para>While fetchnews is running, my modem hangs up.</para>
</question>
<answer><para>
An article that causes the interruption may contain
three plus signs in a row (<quote>+++</quote>), which
many modems interpret as the beginning of a command.
You can change or disable this <quote>escape</quote>
sequence. Consult your modem's manual, register S2 is
a common place to configure this.
</para></answer>
</qandaentry>
<qandaentry><question><para>How can I run fetchnews as regular user (not
root)?</para></question>
<answer><para>For security reasons, this is not possible.</para>
<para>However, there is a tool named <quote>sudo</quote>
that allows a regular, unprivileged user to
impersonate another user, and this can be used to
enable a regular user to run fetchnews.</para>
<para><quote>sudo</quote> is available from
<ulink url="http://www.courtesan.com/sudo/"></ulink>.</para>
<para>If <quote>sudo</quote> is installed on your
system, then run
<userinput>visudo</userinput> as root and
add this line:
<programlisting>username ALL = (news) NOPASSWD: /path/to/fetchnews</programlisting>
Remember to replace
<quote>username</quote> and <quote>/path/to/</quote> with the
user's login and the proper path to
fetchnews.</para>
<para>Now, the user who has been enabled access to fetchnews can
just type <userinput>sudo -u news
/path/to/fetchnews</userinput>
to run fetchnews.</para></answer>
</qandaentry>
<qandaentry>
<question><para>I have unsubscribed from a newsgroup, but
fetchnews still pulls articles for that group.</para></question>
<answer><para>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
<parameter>timeout_long</parameter> parameter) is unsubscribed
and will only stop retrieving articles in it after this
time.</para>
<para>If you are impatient and want to stop retrieving
articles from that group immediately, delete the
corresponding file in the
<filename>/var/spool/news/interesting.groups/</filename>
directory. The articles that are already in your spool are
still subject to the regular <command>texpire</command>
schedule, however.</para></answer>
</qandaentry>
<qandaentry><question><para>How do I stop fetchnews from unsubscribing from
newsgroups?</para></question>
<answer><para>Make sure that your newsreader issues
GROUP or LIST ACTIVE commands for each of
the groups it is subscribed to when checking
for new news, so that leafnode can actually
see which groups are interesting. For
instance, a newsreader configured to read
the whole active file with a LIST command
may lose subscriptions for low-traffic
groups. <link linkend="gnus">See also the Gnus
FAQ below.</link></para>
<para>As a last resort, change your cron job or
ip-up script to run
<userinput>fetchnews -n</userinput> rather than just
<userinput>fetchnews</userinput>.</para></answer></qandaentry>
<qandaentry><question><para>fetchnews is slow, how do I
speed it up?</para></question>
<answer>
<para>If you are using filters, try the
article_despite_filter option (introduced in
leafnode v1.9.33).</para>
<para>If your upstream server does not support
XOVER, try using as few of the
maxage, maxlines, maxbytes, minlines,
maxcrosspost options as possible.</para>
</answer></qandaentry>
<qandaentry><question><para>fetchnews keeps downloading the full newsgroup list
every time it runs</para>
</question>
<answer><para>Watch the fetchnews output for error messages, if you see a
message such as <computeroutput>Reading newsgroups descriptions
failed: 501 bad command usage.</computeroutput> then try adding
<userinput>nodesc = 1</userinput> blow the
server=news.example.org line of the server that showed this error.</para>
</answer>
</qandaentry>
</qandaset>
</sect3>
<sect3><title>texpire</title>
<qandaset>
<qandaentry><question><para>Texpire does not expire
articles.</para></question><answer><para>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
<quote>atime</quote>.</para><para>As a workaround, run
<userinput>texpire -f</userinput>. 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.</para></answer></qandaentry>
<qandaentry><question><para>Texpire message.id counts do
not match the sum of the group counts!</para></question>
<answer><para>This may happen if texpire has been
interrupted previously, crashed, some other
application touched the spool or the spool is corrupt.</para></answer></qandaentry>
</qandaset>
</sect3>
</sect2>
<sect2><title>Problems with particular newsreaders</title>
<qandaset defaultlabel='qanda'>
<qandaentry>
<question id='gnus'>
<para>leafnode loses subscriptions of low-traffic
groups with Gnus.</para>
</question>
<answer>
<para>Check the setting of gnus-read-active-file (you
can use customize-variable to do that), it should be
<userinput>'some</userinput> or
<userinput>nil</userinput>.
</para>
</answer>
</qandaentry>
<qandaentry>
<question id='slrn'>
<para>leafnode loses subscriptions of low-traffic
groups with slrn.</para>
</question>
<answer>
<para>Check the setting of read_active, it should be
<userinput>0</userinput> (the default).
</para>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>When searching news with Netscape, I only get back
<quote>unknown command</quote>.</para>
</question>
<answer>
<para>
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
<quote>options</quote> button which appears in the
<quote>search
messages</quote> window. In the box which appears you have
to select <quote>on your local system</quote>.
</para>
</answer>
</qandaentry>
<qandaentry>
<question><para>Outlook Express locks up.</para></question>
<answer><para>
This can be caused by a corrupted <filename>inbox</filename>
file in Outlook Express. It is said to happen during the
initial install of Internet Explorer. To fix this problem,
go to <quote>Add/Remove Programs</quote>, choose
<quote>Internet Explorer</quote>, then <quote>Repair
installation.</quote>
</para><para>Thanks to Jim Gifford who talked to Microsoft to
find this solution.</para></answer>
</qandaentry>
<qandaentry>
<question>
<para>Tin complains about a missing file
<filename>/var/lib/news/active</filename>.</para>
</question>
<answer>
<para>
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.
</para>
<para>
In the first case, simply invoke tin with
the -r flag: <userinput>tin -r</userinput>. If
this does not help, try to rebuild the
groupinfo file by running
<userinput>fetchnews -f</userinput>.
</para>
</answer>
</qandaentry>
</qandaset>
</sect2>
</sect1>
<sect1 id="backtrace"><title>Obtaining a stack backtrace</title>
<para>This section will tell you how to obtain a <emphasis>stack
backtrace</emphasis>, a special program state output that is
very useful to somebody who is about to debug a crash.</para>
<para>The prerequisite to work is that the program is
<emphasis>not stripped</emphasis>, i. e. it contains the debug
symbols. That means leafnode must have been installed with
<userinput>make install</userinput> rather than <userinput>make
install-strip</userinput>. Note that most packagers (for RPM at
least) use <userinput>make install-strip</userinput> to save space.</para>
<para>To find out if your leafnode installation has been
<emphasis>stripped</emphasis>, type <userinput>file
/usr/local/sbin/leafnode</userinput> (adjust the path as
necessary, packages will usually install to
<filename>/usr/sbin/leafnode</filename> instead), here is a sample
output of an unstripped program:</para>
<para><screen><prompt>$</prompt> <userinput>file /usr/local/sbin/leafnode</userinput>
<computeroutput>/usr/local/sbin/leafnode: ELF 32-bit LSB executable, Intel 80386, version 1,
dynamically linked (uses shared libs), not stripped</computeroutput></screen></para>
<sect2><title>From a core file.</title>
<para>This is simple:
<orderedlist>
<listitem><para>Type <userinput>gdb
<replaceable>PROGRAM</replaceable>
core</userinput>. Replace
PROGRAM by the name of the
program that crashed, for
example fetchnews.</para></listitem>
<listitem><para>Type <userinput>backtrace
full</userinput>.</para></listitem>
<listitem><para>Type
<userinput>quit</userinput>.</para></listitem>
</orderedlist>
</para></sect2>
<sect2><title>Running a program under gdb supervision.</title>
<orderedlist>
<listitem><para>Type <userinput>gdb
<replaceable>PROGRAM</replaceable></userinput>.
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.</para></listitem>
<listitem><para>Type <userinput>run
<replaceable>OPTIONS</replaceable></userinput>, where
you name the options that you would normally pass to the
program itself. Just a plain
<userinput>run</userinput> is
also fine.</para></listitem>
<listitem><para>Wait until the program crashes. The output might
look like similar to this:</para>
<screen><computeroutput>
This GDB was configured as "i686-pc-linux-gnu"...</computeroutput>
<prompt>(gdb)</prompt> <userinput>run -vvn</userinput>
<computeroutput>
Starting program: /tmp/crashme
Program received signal SIGSEGV, Segmentation fault.
main () at crashme.c:4
4 *x = 4;
<prompt>(gdb)</prompt>
</computeroutput></screen>
</listitem>
<listitem><para>Type <userinput>backtrace
full</userinput>, this is the
desired <emphasis>stack backtrace</emphasis>.</para></listitem>
<listitem><para>Type <userinput>quit</userinput> to leave
gdb.</para></listitem>
</orderedlist></sect2>
<sect2><title>From a running/hanging leafnode
program.</title>
<orderedlist>
<listitem><para>Find out the Process
ID of the hanging leafnode
program. Type
<userinput>ps axw | grep
<replaceable>PROGRAM</replaceable> | grep -v
grep</userinput> on BSD
systems and Linux,
replacing
<replaceable>PROGRAM</replaceable> by the
name of the program. Use
<userinput>ps -ef</userinput>
instead on SysV systems such
as Solaris.</para>
<para>You will get an output
like:
<screen> 1995 ? S 0:00 /usr/local/sbin/leafnode
</screen> 1995 is the
Process ID.</para></listitem>
<listitem><para>Then attach gdb:
<userinput>gdb
<replaceable>PROGRAM</replaceable>
<replaceable>12345</replaceable></userinput>,
replacing
<replaceable>PROGRAM</replaceable> by the
program's name and
<replaceable>12345</replaceable>
by the PID that you have just
found out.</para></listitem>
<listitem><para>Type
<userinput>backtrace
full</userinput>.</para></listitem>
<listitem><para>Type
<userinput>detach</userinput>.</para></listitem>
<listitem><para>Type
<userinput>quit</userinput>.</para></listitem>
</orderedlist>
</sect2>
</sect1>
<sect1 id="redhat-xinetd">
<sect1info> <author>
<firstname>William</firstname>
<surname>Hooper</surname>
</author>
</sect1info>
<title>Red Hat and the inetd vs. xinetd issue.</title>
<para>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 <userinput>rpm -qa
| grep &inetd;</userinput> will show you if either inetd
or &xinetd; is installed. The <command>service</command> and
<command>chkconfig</command> 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;.</para>
<para>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. </para>
<para>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. </para>
<para>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;): </para>
<orderedlist>
<listitem><para><emphasis>Best</emphasis>
- If you have registered for Redhat's up2date
service, just type "up2date xinetd" as
root.</para></listitem>
<listitem><para><emphasis>Next Best</emphasis>
- 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 <userinput>rpm -ivh
xinetd-2.3.9-0.73.i386.rpm</userinput>, or have
RPM download it for you by using (again, as root)
<userinput>rpm -ivh
http://updates.redhat.com/7.3/en/os/i386/xinetd-2.3.9-0.73.i386.rpm</userinput></para>
</listitem>
<listitem><para><emphasis>Worse</emphasis>
- Install the RPM from the original CD. This is usually the worse
option because the updates (used above) are released to fix security issues.
</para><para>
(All as root) First mount the first RH CD by putting it in the CD-ROM and
doing a <userinput>mount /mnt/cdrom</userinput>, and install the
RPM similar to this: <userinput>cd
/mnt/cdrom/Redhat/RPMS/xinetd-2.3.7-2.i386.rpm</userinput>.
</para></listitem>
</orderedlist>
</sect1>
</article>
