2002 10 17

                    LINUX NEWS
          October 17, 2002 -- Issue #103


1) Sean’s Notes

2) Linux News

Linux.com To Match Microsoft Donations
Red Hat Linux 8.0 Tops Desktop Class
India Moving to Linux
A Look At Gentoo

3) Linux Resources

How Many Disks Are Too Many for a Linux System?
Active Directory Tool... For Linux
Log Files for Analysis
Conserve Energy... With Linux
Basic Makefiles

4) App o’ the Week

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1) Sean's Notes

The past couple of weeks I've been going over mail.  First it
was the flow of mail over the Internet, from your mail client
(MUA), to your Mail Transfer Agent (MTA), to the recipient's
mailbox, and then into his MUA.  Last week looked at the
configuration of the PostFix MTA, which leaves one thing,
namely getting the mail from your spool onto your desktop.

Two protocols are helpful for doing this, the Post Office
Protocol Version 3 (POP3), and the Interactive Mail Access
Protocol Version 4 (IMAP4).

POP is the simpler of the two; though it can do a lot more,
it's often used to grab your whole mail spool and delete it
from the server.  ISPs love it--they store your mail until you
pick it up and get it off their hands.

My favourite POP implementation comes courtesy of Qualcomm,
and is called "qpopper".  You can grab the sources from:


To install it, uncompress the tarball:

# tar -xzf qpopper4.0.4.tar.gz

Change into the directory:

# cd qpopper4.0.4

If you run "./configure --help", you'll see all the options that
you can set in this versatile daemon.  I've always used:

# ./configure --enable-specialauth --enable-servermode
    --with-openssl \ --enable-spool-dir=/var/spool/mail
    --enable-uw-kludge  --enable-poppassd

Yikes, eh?  Since the POP daemon was one that I always kept up
with upgrades, I made an RPM out of it so it would always build
the same.  Assuming you're using Red Hat, you can do the same,
too.  Jump on over to:


- Save the content to /usr/src/redhat/SPECS/qpopper.spec
- Move qpopper4.0.4.tar.gz to /usr/src/redhat/SOURCES
- Run "rpm -ba /usr/src/redhat/SPECS/qpopper.spec" as root
- Install the rpm from /usr/src/redhat/RPMS/i386

Probably the source of another article or two, but building
software as an RPM lets you ensure that you have it under
package management, and that you always build the software the
same (try remembering which options you used a year later!).  If
4.0.5 comes out, copy the tarball to SOURCES, bump the version
number within qpopper.spec, rerun rpm -ba qpopper.spec, and rpm
-U the resulting RPM.  Wondering what version of popper you're
running?  rpm -q qpopper

If you didn't go the rpm route, you can run:

# make
# make install

after you've run ./configure to do much the same thing, but
without the package management.

Though there are dozens of options you can pass to the daemon,
you can get by without them.  To activate qpopper, we have to
tell inetd about it.  If you haven't caught any of my articles
on inetd, its job is to listen for connections to the POP port
(TCP 110), and then spawn off a qpopper process to handle it.
Saves a lot of memory if there are few connections!

Users of the older inetd will want to add the following line
to inetd.conf:

pop3    stream  tcp    nowait  root    /usr/sbin/tcpd  popper

If you're using the newer xinetd, create /etc/xinetd.d/popper
with the following:

service pop3
        flags           = REUSE
        socket_type     = stream
        wait            = no
        user            = root
        server          = /usr/sbin/popper
        log_on_failure  += USERID
        disable         = no

Either way, it tells inetd to listen on the pop3 port, and to
run /usr/sbin/popper when it sees it, that is, once you restart
inetd!  They'll both respect wrappers, which we'll use to
prevent everyone on the Internet from connecting to the POP daemon:

popper: ALL

popper: localhost, 192.168.1.

(I'm making the assumption here that your internal network is, change the line as appropriate if I was wrong.)

If you want to learn more about controlling access with
hosts.allow and hosts.deny, "man 5 hosts_access" is for you.
xinetd users get additional control with the man page for

So, we've built and installed a POP daemon.  Inetd is set up to
listen for POP requests, and has been restarted.  Access
control?  Check.  I guess we're ready to try it out!

# telnet localhost pop3
Connected to localhost.
Escape character is '^]'.
+OK Qpopper (version 4.0.4) at poochie starting.
+OK Pop server at poochie signing off.
Connection closed by foreign host.

(that was me typing QUIT, by the way).

Those interested in protocols might note that SMTP uses numeric
codes for status, while POP uses either "+OK" or "-ERR".  So
much for standards, eh?

If you got a "connection refused", then it's likely that
something went wrong with the inetd setup.  If it connects and
kicks you out before giving a banner, then your ACLs are to blame.

At this point you're ready to point your mail client to your
brand new POP server.  Have fun!

Though I'll cover the second protocol, IMAP, in an upcoming
newsletter, it is pretty much the same as what we did today.
Some distributions even include the University of Washington
version, which is the one I use myself.  Install, enable in
inetd, connect (port 143 this time).

Even if you're not running your own domain at home, a POP server
is handy if you want to read root's email on another machine.
Thus, you can get your logs on your desktop, without having to
use a text-based email client.

Long live the Penguin,


2) Linux News

Linux.com To Match Microsoft Donations

Microsoft has offered schools some free licences to their
product, content that in a few years they'll have paying
customers. Linux.com has exactly the same offer, but with no
strings! Take all the Linux you want! A very funny, but
accurate, article.


Red Hat Linux 8.0 Tops Desktop Class

eWeek took the new Red Hat 8 for a spin, and from the
perspective of the desktop, was impressed. No screenshots, but
still a good article.


India Moving to Linux

"INDIA'S GOVERNMENT Department of Information Technology has
announced a sweeping initiative to move the entire country to
Linux as its "platform of choice" in place of higher cost
'proprietary' software, reports the India Times subsidiary
Economic Times."


A Look At Gentoo

Gentoo Linux's angle is that everything is compiled from source.
I never realized some of the implications of this until I read
this article. It definitely puts Gentoo on my "gotta try" list!


3) Linux Resources

How Many Disks Are Too Many for a Linux System?

Linux makes a great file server, but in many cases, the
underlying computer imposes some restrictions on how much space
you can cram into a single machine. Here's an interesting look
at disk capacities.


Active Directory Tool... For Linux

"adtool is a unix command line utility for Active Directory
administration. Features include user and group creation,
deletion, modification, password setting, and directory query
and search capabilities."


Log Files for Analysis

Logs aren't only for debugging, they're a valuable forensic
tool. This article from SecurityFocus goes over some ways to
monitor your logs, and keep one step ahead of the Blackhats.


Conserve Energy... With Linux

"AcquiSuite is a computerized device (manufactured by Obvius --
Portland, OR) which is used for building automation and energy
management. The device can lower the cost of operating a
building by collecting and reporting information in a reliable,
timely, and inexpensive manner." And, it runs Linux!


Basic Makefiles

Programmers use Makefiles to save recompiling code that's
already compiled, and to automate the process. It's also a handy
system administration tool. This article goes over what basic
elements go in a Makefile.


4) App o' the Week

I'm always on the lookout for dynamic DNS providers, especially
if they're free. Here's one I just found that fits the bill.
Also great if you've been following along with the email
discussions; with one of these dynamic names you can have a
nicer domain name, and not have to fork out the cash for a .com.


(C) 2002 BrainBuzz.com, Inc. All Rights Reserved.

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