Unix system administration bulletin, 2000

NEWS CONTENTS

• 20000820 : Tutorial Compiling and installing software from sources by Daniel Robbins ( Tutorial Compiling and installing software from sources, Aug 20, 2000 )
• 20000729 : Are Buffer Overflow Sploits Intels Fault ( Are Buffer Overflow Sploits Intel's Fault, Jul 29, 2000 )
• 20000729 : Tricks with etc_issue ( Linuxuser.co.za )
• 20000723 : Mailing From Scripts ( Focus On Linux Issue #92 )
• 20000722 : OReilly Network What is a Network Administrator Anyway ( O'Reilly Network What is a Network Administrator Anyway, Jul 22, 2000 )
• 20000712 : Using expect for System Administration ( Using expect for System Administration, Jul 12, 2000 )
• 20000712 : RootPrompt.org ( RootPrompt.org, )
• 20000619 : Trust and the System Administrator ( RootPrompt.org )
• 20000604 : Monitoring your desktop machine by gh0ul ( June 04, 2000 , LinuxFreak )
• 20000509 : inetd and inetd.conf - Managing Your Systems Internet Switchboard Operator ( inetd and inetd.conf - Managing Your System's Internet Switchboard Operator, May 9, 2000 )
• 20000421 : OReilly Network: CYA for System Administrators; Things to keep in mind in our litigious society ( O'Reilly Network: CYA for System Administrators; Things to keep in mind in our litigious society, Apr 21, 2000 )
• 20000127 : Administering Linux using CVS. ( Jan 27, 2000 )
• 20000123 : Version 2.0 of the Netware file system ( Version 2.0 of the Netware file system, Jan 23, 2000 )
• 20000123 : System Administration Made Simpler, Part 4 ( System Administration Made Simpler, Part 4, Jan 23, 2000 )
• 20000120 : GURU GUIDANCE Big Brother Is Watching ( Linux Magazine )
• 20000103 : Portable Unix Toolkit ( Portable Unix Toolkit, Jan 3, 2000 )

Old News ;-)

[Aug 20, 2000] Tutorial Compiling and installing software from sources by Daniel Robbins

Let's say that you find a particular application that you'd like to install on your system. Maybe you need to run a very recent version of this program, and this most recent version isn't yet available in a packaging format such as RPM. Perhaps this particular application is only available in source form, or you need to enable certain features of the program that are not enabled in the RPM by default.

Whatever the reason, whether of necessity or simply just because you want to compile the program from its sources, this tutorial will show you how.

[Jul 29, 2000] Are Buffer Overflow Sploits Intel's Fault

Slashdot interesting discussion about problems with C

[Jul 29, 2000] Tricks with etc_issue

Linuxuser.co.za

When your Linux System boots it starts "getty" processes on a number of virtual terminals on your system. When getty starts, it prints the contents of /etc/issue to the terminal. To customize the look of your console, all you have to do is edit /etc/issue.

You can also add colour by using the colour capabilities of the Linux console. The Linux console, like almost any other existing terminal, has escape sequences that can be used to change the appearance of text on screen. Piping the following script into /etc/issue:

	#!/bin/sh

	spaces(){
	        COUNT=0;
 	       while [ $COUNT -lt $1 ]; do
 	               echo -ne " ";
 	               COUNT=$[$COUNT+1]
 	       done
	}

	esc="\033["
	echo -ne "${esc}H${esc}J\n${esc}44;37;1m"
	WELCOME="Welcome to "`hostname`" running Linux "`uname -r`
	CHARS=$[(80-`echo $WELCOME | wc --chars`)/2]
	spaces $CHARS
	echo -ne $WELCOME
	spaces $CHARS
	echo -ne "${esc}0m\n\\l "

should produce this result:

... ... ... ... ...

[Jul 23, 2000] Mailing From Scripts

Focus On Linux Issue #92

The old Unix mailer at /bin/mail is one of the programs that really helped to launch the Internet as we know it today. In days gone by, it

was one of the most used binaries on any Unix workstation. Today, the /bin/mail binary can still be used, but is horribly outdated -- it's a text-only mailer with almost no features at all.

It is good, however for one thing: automated mailing, such as sending e-mail from a shell script. To send mail with the /bin/mail program, use this syntax:

  mail -s "subject" touser@address < body_text

For example, if your e-mail address is [email protected], and you needed to have the login information from the last command on a given system sent to you every night at a given time, you could create a cron job which called this command:

  last | mail -s "Login information" [email protected]

When executed, this command would send the output from the last command to your e-mail box with the subject given. There are many uses for the /bin/mail program when employed this way in scripts; use your imagination.

Focus on Linux Forum

/bin/mail other than text

You can use bin mail to also mail attachments. This was not mentioned in the article so I thought I might help out a few hapless souls.

To use /bin/mail to mail a attachment you must also have uuencode installed. Not to worry though, most distributions include this by default. Anyhow on to the good stuff.

So I'm in my home directory /home/possum and there is a file in there called attachment.txt. I can send this file two ways:

The first makes the attachment.txt show in the mail, in other words the mail will contain the contents of attachment.txt. To do this I enter the command "mail [email protected] < attachment.txt".

The second way send attachment.txt as an attachment. I had wanted to
do this many times and was unable to until I found uuencode could make this happen. To send it as an attachment I would enter the command "uuencode attachment.txt attachment.txt | mail [email protected]". In the command line the first attachment.txt is the name of the file I want to send. The second attachment.txt is the name of the attachment the recipient will get. Pipe that to mail and Viola you have sent an attachment from a command line or shell script. Happy scripting, Paul

[Jul 22, 2000] O'Reilly Network What is a Network Administrator Anyway

Linux Today

"We've seen the terms "system administration" and "network administration," in the title of this column for example. There are some obvious system administration tasks, such as installing or upgrading system software like the kernel or libraries and managing user accounts and disks space, so you probably have some idea of what a system administrator does. What does a network administrator do, and how do you differentiate between system administration and network administration? Bear with me while I think out loud on the subject, and perhaps we'll have some idea by the end of this column."

"In a small environment, the difference is fairly moot -- the same person or team will probably fill both roles anyway. In large IT environments, perhaps a large web-hosting company or a large ASP, the question has relevance. There will be enough work to have teams of systems administrators and teams of network administrators, and at some time it will be necessary to work out who is going to do what, to what, and when."

"I'm not going to attempt to define the role of the network administrator in this column. Instead I'll share my thoughts on the subject and add a dash of the larger context of telecommunications management in the hope that you might make some sense of it."

[Jul 12, 2000] Using expect for System Administration

RootPrompt.org

For example the following program runs rlogin to the named machine and then sets your DISPLAY to whatever it was on the source machine.

#!/depot/path/expect --
# xrlogin - rlogin but with current DISPLAY
#
# You can extend this idea to save any arbitrary information across rlogin
# Don Libes -  Oct 17, 1991.

if {[llength $argv] != 1} {
        puts "usage: xrlogin remotehost"
        exit
}

set prompt "(%|#|\\$) $"                ;# default prompt
catch {set prompt $env(EXPECT_PROMPT)}

set timeout -1
eval spawn rlogin $argv
expect eof exit -re $prompt
if [string match "unix:0.0" $env(DISPLAY)] {
        set env(DISPLAY) "[exec hostname].[exec domainname]:0.0\r"
}
send "setenv DISPLAY $env(DISPLAY)\r"
interact

[Jun 19, 2000] Trust and the System Administrator

RootPrompt.org

"A System Administrator has a strange relationship with the equipment they manage, with the people using their system and with the world outside their systems. They have to walk a fine line between making their systems unusable and leaving them unsecured or unreliable. To make things even more complicated the line is different for each and every situation. In this article I will overview some of the choices and decisions that a System Administrator must understand and make when building or maintaining their systems."

"I will look at each general area from the point of view of who or what the System Administrator is trusting and some of the factors involved. I have chosen as examples to discuss trusting the OS, hardware, backups, users, physical site, other machines, network and the world."

[Jun 04, 2000] Monitoring your desktop machine by gh0ul

June 04, 2000 | LinuxFreak

Many people who start out with Linux using just X, never notice a lot of the things that can go on with a Linux system. Some of those things should be monitored or at least kept an eye on. In this article we will go over a couple methods of watching over your Linux box from the X windowing System.

First off, we will go over a traffic monitor called 'trafshow'. trafshow is a light and easy traffic monitor that displays information about connections to your system, for example, if someone telnets to you, it will display their ip, the protocol, and port.. very simple information for just keeping an eye open. You can get it from here. Grab trafshow-1.3.tar.gz, un-tar and compile it, you should be able to simply untar it and issue a make && make install in the directory (must be root for the make install) After that, go ahead and open an xterm, I suggest using the flags:
xterm -bg black -fg white Then you can su and start trafshow, or some may prefer to give it root permissions so they would not need to su anymore, but others might prefer to keep it root only, so that if you have users on your system whom you don't want to see your connections, you'll still be good to go. It's suggested that you keep the terminal open with trafshow running at all times, so if you are ever curious about a connection, you can simply take a look and see what's going where.

Another pretty popular traffic monitor is iptraf, it does a lot of the same as trafshow, yet can be configured more, and also will log data. You can find it here: ftp://ftp.cebu.mozcom.com/pub/linux/net/iptraf-2.2.1.tar.gz

Some other helpful network monitoring tools:

• (tcpflow, tcpdump, and trafshow+rvnamed below all require libpcap, which can be obtained at ftp://ftp.ee.lbl.gov/libpcap-0.4.tar.Z)
• tcpflow is a utility for showing TCP packets contents in cleartext.. in an easy to view manner (layer 2)
  URL: ftp://ftp.circlemud.org/pub/jelson/tcpflow/tcpflow-0.12.tar.gz
• tcpdump is a layer 3 traffic monitor and data acquisition.
  URL: ftp://ftp.ee.lbl.gov/tcpdump-3.4.tar.Z
• trafshow+rvnamed is a version of trafshow (like above) merged with nvnamed from iptraf.
  URL: http://www.unix.gr/firesoft/trafshow-angelos.tar.gz
• Portsentry is a wonderful tool for detecting port scans, you can even set it up to execute scripts like perhaps a notify-by-email script.linuxnewbie also has a pretty good review on setting portsentry up.
  URL: http://www.psionic.com/tools/portsentry-1.0.tar.gz
• Another neat application (for monitoring log files) is root-tail, you can find it here: http://goof.com/pcg/marc/data/root-tail-0.0.6.tar.gz root-tail, similar to the normal Unix command 'tail' (will tail the end of a file) , yet root-tail prints it to your desktop (directly to the X11 root window).
  you can customize it quite nicely also, and tail things to your root window like syslog, or any other logs that might be of interest to you.

  Example Usage:
  root-tail -g 80x25+100+50 /var/log/messages,green /var/log/secure,red,'ALERT'

These are NOT full proof anti-hack methods to take on your system, but these should help you out a bit, and they are always handy to go along with normal system administration.

[May 9, 2000] inetd and inetd.conf - Managing Your System's Internet Switchboard Operator

BSD Today

The file /etc/inetd.conf is vitally important to your system's security and well-being -- especially if your system has a 24x7 connection to the Internet. Many common security holes in UNIX systems (and UNIX-like systems such as Linux) are the result of entries in inetd.conf that should have been "commented out" or removed. On the other hand, an omitted entry can cause your system to consume extra memory or swap space, or make it more susceptible to denial of service attacks."

"As the name implies, /etc/inetd.conf is the configuration file for inetd, the "Internet daemon." In the early days of UNIX, when a 10 MB hard drive was considered to be huge and system memory was measured in kilobytes instead of megabytes, inetd was devised as a way to save valuable RAM and disk swap space."

"Prior to inetd, each "daemon" -- that is, a program which provided an Internet service -- had to be in memory, waiting for requests, at all times. But there was a problem: keeping that code loaded and ready to run consumed valuable system resources. As the repertoire of services provided by systems on the Internet (then the ARPANet) grew, systems were in peril of being overrun by daemons, leaving no space for programs that did other work."

"Enter inetd. Acting as a sort of switchboard operator, inetd fields incoming requests for other daemons. When a "call" comes in, inetd starts up a copy of the appropriate daemon and "transfers the call" to it. Thus, no Internet daemon -- other than inetd itself, of course -- must remain in memory when it's not providing a service."

[Apr 21, 2000] O'Reilly Network: CYA for System Administrators; Things to keep in mind in our litigious society

"Doing the wrong thing in the cause of making your network "more secure" can land an unlucky administrator in a duel with the legal system. This is more likely when your actions come as a surprise or are viewed in a bad light by others who question your authority or motives to be doing what you're doing. With all the sound and fury in media about evil hackers, it's a good idea to consider how to protect yourself ahead of time."

"The sheer power of the systems administration function intimidates many users and management types when they stumble into the realization of just what can be done with root privileges. The question that shakes out of this is pretty simple: How can I do my job, run a system or network safely and securely without winding up on the wrong end of a subpoena?"

"...it's a good idea to make sure that your role and your responsibilities are fully specified. By "fully specified" I... mean that... your job description should be complete and list not only the hardware and software you support, but what management areas that role includes."

[Jan 27, 2000] Administering Linux using CVS.

Much emphasis has of late been put on making Linux easier to manage. Typically the model used it that of a single user managing one or more systems. However, once mutiple administrators and automated scripts are all altering the configuration for a single machine the sutiation becomes somewhat more complex. This problem is in essence very similar to the problem software developers face when a team is working on a source tree. There are many solutions to this problem, one of the most popular being Concurrent Versions System or CVS.

Twinkle-Toes Release 4th February 1999.

• html
• dvi
• postscript
• uncompressed postscript
• latex source

[Jan 23, 2000] Version 2.0 of the Netware file system

announced by the Timpanogas Group.

It is currently only available in binary form. Source is evidently forthcoming, but has been delayed due to some weirdness that is best read directly from the announcement.

[Jan 23, 2000] System Administration Made Simpler, Part 4

Who says system administration can't be fun? My lovely and wonderful wife, Sally, is busy using this week's system administration feature to play Kpoker, the K Desktop Environment poker game. She's not busy checking on logs, administering print queues, or even running a process analyzer. She's playing poker. Of course, earlier on, I took control of her Windows 95 PC and started to edit a letter she was working on, so it probably serves me right. In the interest of telling you all about this marvelous tool, I decided to connect to her Windows 95 session and see how the KDE poker game she was playing on our server was doing. Turns out she was losing all our money. Well, that's gambling for you.

Oh--did I mention I am talking about a fantastic remote administration tool that works with not only Windows, Solaris, DEC Alphas running OSF1, but even that old favorite of the desktop publishing world, the MacIntosh?

This great tool is VNC (Virtual Network Computing) from AT&T Laboratories in Cambridge, England. VNC is a package that allows you to view other computer desktops from your own desktop. For instance, I could be running an X server on a Linux machine from a Windows 95 or NT box, or doing the reverse. I can do it from my internal network or across the Internet.

The system administrator in a large company with a number of Windows workstations knows the headaches of all the simple "operator" error calls that nonetheless require a great deal of work and time as you walk the user through the right steps to solve their problems. Wouldn't it be great if you could take control of their desktops and do it for them while they watch and learn? Now, I know there are commercial packages that can do this, but not necessarily from your Linux desktop. They also cost more than VNC.

That's right. VNC is distributed free of charge.

[Jan 20, 2000] GURU GUIDANCE Big Brother Is Watching

Linux Magazine

Fortunately, this Big Brother is truly your friend. However, like its Orwellian namesake, it is constantly on the lookout for things it doesn't like, waiting to sound an alarm. I am talking about a systems-monitoring tool developed by Sean MacGuire of The MacLawran Group (http//www.maclawran.ca/bb-dnld/) called Big Brother.

Big Brother does most things that you'll find in commercial monitoring tools; it can let you know when a machine on your network is down or becoming overloaded or when a filesystem is getting too full; it can tell you when specific processes are or are not running on clients; it can even page you when a specific event occurs. It can be used to monitor Unix, Linux, Windows NT, and NetWare clients.

One of the main reasons you'll want to try out Big Brother is because of its simplicity. It is composed of just a handful of scripts and programs, which collect information and report it to a central server, which displays everything in an accessible HTML format. Big Brother's scripts are easy to change and reconfigure, allowing you to customize the software to suit your network.

Although it is not covered directly by the GNU General Public License, you can download Big Brother for free from the MacLawran Group's Web site. It is covered by a "fair use" license, which requires written permission from the MacLawran Group to redistribute it.

[Jan 3, 2000] Portable Unix Toolkit

Most of these scripts are Korn shell scripts, a few are Perl or Expect scripts. The Demo Edition, which is distributed as freeware, contains 11 scripts. The Professional Edition contains a total of 49 scripts and includes all the scripts in the Demo Edition as well as the login environment files. The Enterprise Edition contains a total of 78 scripts and includes all the scripts in the Demo Edition as well as the login environment files. (Some of the Enterprise Edition scripts work only on Solaris, AIX or HP-UX - see the list below.) The Master Edition includes the Professional Edition and the Enterprise Edition for a total of 106 scripts and over 7,000 lines of code. Click on the script names (below) to view the manual pages for the scripts.

The Portable Unix Shell Environment

The Portable Unix Shell Environment (PUSE) is a set of Korn shell login environment files and about 80 Korn shell, Perl and Expect scripts that have been ported to several versions of Unix. It is distributed at no charge as open source software. The scripts, which can be used independently of the login environment files, include general utility scripts and systems administration scripts.

The Portable Unix Shell Environment allows the user to, for example:

• Substitute one string for another in all the text files in a directory hierarchy.
• List all the subdirectories in one or more directories, including symbolic links to directories.
• Copy a file to multiple remote hosts, with backup of the target file on each host.
• List the city or region for a telephone area code or vice-versa.
• Use a single set of Korn shell login environment files (.profile, .kshrc) in a heterogeneous Unix network.

The PUSE has been downloaded 825 times since February 1999. It has been tested on Solaris 2.5.1, 2.6, HP-UX 10.00, 10.20, AIX 3.2.5, 4.1.4, 4.3.2, Ultrix 4.3 and UWin-NT 1.6, 1.68. The scripts were written from scratch; they contain no viruses, worms, Trojan horses, trapdoors, etc. The PUSE is Y2K compliant.

Etc

Society

Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers :   Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism  : The Iron Law of Oligarchy : Libertarian Philosophy

Quotes

War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda  : SE quotes : Language Design and Programming Quotes : Random IT-related quotes :  Somerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose Bierce :  Bernard Shaw : Mark Twain Quotes

Bulletin:

Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 :  Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method  : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law

History:

Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds  : Larry Wall  : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOS :  Programming Languages History : PL/1 : Simula 67 : C : History of GCC development :  Scripting Languages : Perl history   : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history

Classic books:

The Peter Principle : Parkinson Law : 1984 : The Mythical Man-Month :  How to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Hater’s Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite

Most popular humor pages:

Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor

The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D

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Last modified: March 12, 2019