LINUX NEWS
RESOURCES & LINKS FROM BRAINBUZZ.COM
Thursday, August 16, 2001
Read By 7,000 Linux Enthusiasts Weekly!TABLE OF CONTENTS
1) Sean’s Notes
2) Linux News
Happy Birthday, Linux
More on Largo
KDE 2.2 is Released
2.4.8 Released3) Linux Resources
What is Cygwin?
TrinityOS
Serial Console HOWTO
Mandrake Campus
Learning with NMAP4) App o’ the week
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1) Sean’s Notes
“A man with a watch knows what time it is. A man with two watches is never sure.” – Segal’s Law
If you’ve operated more than a couple of computers together, you know how true this can be. Keeping clocks synchronized between multiple computers is a nightmare. Windows folks have their “net time” command, which doesn’t offer too much accuracy, but is better than nothing.
Enter the network time protocol (NTP). NTP allows a client to grab the current time from the server over a network. The protocol is even designed to take into account network latency, local clock drift, and several other factors such as two servers giving two separate times.
Rather than having everyone get their time from one server, NTP assigns a “stratum” to each server, and allows servers to query each other. A stratum 1 server gets its time directly from an official time source, usually by GPS. A stratum 2 server gets its time from a stratum 1 server via NTP. A stratum 3 server gets its time from a stratum 2 server, and so on. Most of us will want to get our times from a stratum 2 or 3 server, since the time difference is almost insignificant. (It’s also said that if you need that kind of accuracy, you’re better off getting a GPS receiver and becoming a stratum 1 yourself)
Installation of NTP is straightforward. Grab the latest sources from www.ntp.org. Unpack the distribution:
tar -xzf ntp-4.x.x.tar.gz
cd ntp-4.x.x
./configure
…
make
…
make install
It’ll install a few binaries, by default in /usr/local/bin. “ntpd” and “ntpdate” are the most important ones.
ntpdate sets your local clock to the time on a specified server. ntpd is a daemon that periodically checks ntp sources and adjusts your clock. Note that ntpdate will do an abrupt change, while ntpd will slowly migrate your time to the correct time. However, if you’re too far off (1,000 seconds), ntpd will refuse to run. This is why I generally execute “ntpdate” before “ntpd” in my startup scripts.
The next step is to find yourself a time server or two (or three, but no more than three for now).
http://www.eecis.udel.edu/~mills/ntp/clock2.htm
has a list of publicly available servers running at stratum 2. Take note! Some request that you either email a notification, or ask permission, before using. Please respect the server’s wishes. For now, I’m going to select numbers 19 and 20, the Canadian National Research Council and University of Regina respectively. They’re both relatively close to me, so they’ll make great servers.
/etc/ntp.conf is the default configuration file. We’re going to do the easiest config possible, allowing our computer to be both an NTP client and server:
server time.nrc.ca server timelord.uregina.ca driftfile /etc/ntp.drift
Servers are specified with the “server” command, and the “driftfile” tells ntpd where it can keep track of clock drift.
Once that’s done, fire up ntpd. It’ll fork off to the background, so it’s safe to put in startup scripts:
ntpd
And, /var/log/messages should see:
ntpd[17161]: ntpd 4.0.99k23 Tue Aug 7 21:30:12 CDT 2001 (1) ntpd[17161]: precision = 20 usec ntpd[17161]: kernel time discipline status 0040 ntpd[17161]: frequency initialized -73.714 from /etc/ntp.drift
I also set my clock back a day to show what happens:
ntpd[17161]: time error 132771 over 1000 seconds; set clock manually
And ntp dies. The solution is to ntpdate your system first:
ntpdate time.nrc.ca
15 Aug 14:06:47 ntpdate[17232]: step time server 132.246.168.164 offset 132770.937557 sec
Once your primary computer is set up to get time, you can use the same technique for other machines under your control. This time, though, specify your own server as the server.
For those looking to add Windows machines into the mix, I have had good luck with a program called “Tardis”.
You can read more about the system that keeps the master clock, and how it all works, at:
http://tycho.usno.navy.mil
Long live the Penguin,
Sean mailto:swalberg@brainbuzz.com
Visit the Linux News Board at http://boards.brainbuzz.com/boards/vbt.asp?b2
2) Linux News
Happy Birthday, Linux
August 25th marks the 10th birthday of Linux. There are celebrations all over the world, so check this site out to see if there is one in your area!
http://www.linux10.org/
More on Largo
A while ago I gave you a link about the City of Largo, who had converted to thin clients using KDE on a Red Hat server. This story was written by someone who visited the place, and talked to some of the users about their experiences.
http://www.newsforge.com/article.pl?sid/08/10/1441239
KDE 2.2 is Released
All you KDE fans out there, it’s time to upgrade. 2.2 promises more stability, increased speed, improvements to Konqueror, and a lot of new features.
http://www.kde.org/announcements/announce-2.2.html
-
8 Released
So much for the pace of upgrades slowing down– 2.4.8 is out. Luckily, there don’t appear to be any changes that necessitate an immediate upgrade.
http://www.kernel.org/pub/linux/kernel/v2.4/ChangeLog-2.4.8
3) Linux Resources
What is Cygwin?
The answer to this, and many other questions, can be found in the Cygwin FAQ. Cygwin is a project that ports development tools from Unix to Windows. It’s written such that many Unix applications will compile directly on Windows. Even if you don’t need that, it provides the familiar shells and utilities to the Windows environment.
http://cygwin.com/faq/faq_toc.html
TrinityOS
The TrinityOS Documentation is a step-by-step set of instructions for building a secure Linux box. Most services you’d need on a gateway are here, and the instructions are easy to follow.
http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html
Serial Console HOWTO
Running a Linux box “headless” (i.e. no keyboard or video) is a great way to save space and money. There may be occasions where you need console access to a box, and having to lug in a monitor is not desired. Like other UNIXes, Linux can have a serial port act as the console port, so you can get access to the box right from the LILO prompt.
http://www.linuxdoc.org/HOWTO/Remote-Serial-Console-HOWTO/
Mandrake Campus
The Mandrake campus offers free online training, on topics from basic tools to server services. It’s well done, easy to navigate, and best of all, free!
http://www.mandrakecampus.com/
Learning with NMAP
Not only does this tutorial show you how to scan your network with NMAP, it shows you what’s under the hood, to help you understand how TCP works and to see when your network is being scanned. An excellent article on a utility that should be in every administrator’s toolbox.
http://linuxfocus.org/English/July2001/article170.shtml
4) App o’ the week
This week’s application, coinciding with the release of KDE 2.2, is KDevelop, an integrated development environment (IDE) for coders. Don’t let the ‘K’ fool you, this baby has wizards for both Qt and GNOME applications, not to mention regular C/C++ programming.
http://www.kdevelop.org/
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