Davrom Consulting Pty Ltd

Established Since 2001
PO Box 1644, Sunnybank Hills, Qld, 4109
ABN: 81 096 990 804

Site Time: 28 January 2023 - 20:43

Back to Newsletters

KEYWORDS=sar, cpqmon, u386mon, sysstat, DAVROM CONSULTING Newsletter - Issue # 25 - Dated: Tue Sep 28 14:52:50 EST 2004

From the desk of David Clark

Support for us lately continues on to be SCO, Linux, SnapGear, ePipes and
all the good UNIX/Linux technologies they encompass. Also seems to be the
month for working with various models of UPS (Uninterruptible Power
Supply) so I have done a small article on them.

My personal thanks to Simon who gave me nudge to get this newsletter out
some time back....

I would like to thank the reader for their time in reading this newsletter.


UNIX Quote

My life is a UNIX shell, what more would I want.

Who died and left you in charge?

We've all heard this famous expression at some point in our life but I
didn't think it would re-appear in the I.T industry, more so the Internet

Having switched to broadband cable in February, we went from a fixed dialup
IP address to one that changes every few months if and when the link goes
down (which it hardly ever does). In both our connection cases, the permanent
IP dialup and the broadband IP assignment, we have found that some e-mail
addresses we were sending to were not receiving the e-mails and we in turn
received notification from "so called" Internet e-mail abuse/spam "blockers"
that our IP addresses were in the dynamically allocated IP lists for the
Internet and they were refusing to allow the e-mails through. In a nutshell,
they blocked our e-mail server and their response robot's (you will
virtually never get a human response) told us to push the e-mail through
our local ISPs SMTP server.

While this is fine for the most part for 90% of organisations, some ISPs do
monitor the e-mail volume being sent via their servers and if a large
volume of e-mails are sent from an originating e-mail address through their
SMTP servers in one hit, they in turn may purge the e-mail in the fear it
is spam.

A further issue to this was while we obeyed the rules of one abuse/spam
blocker by going through the ISPs SMTP server, we then found some e-mails
were blocked as the ISPs SMTP server was on the black-list with another
abuse/spam blocking service. This is nothing short of binding someone's
feet and hands, throwing them into the ocean and then saying, "Now you need
to swim." For business this kind of maverick blocking on non-spam e-mail
by self-appointed marshalls no doubt impacts on profitability as you
can't communicate with your customers.

In our experience running your own spam blocker (such as SpamAssassin) on
a local server is still one of the better ways to fight the current
epidemic of spam rather than rely on a third party - at least until
legislature catches up with the Internet and we can outlaw spam (by the
year 3000 perhaps).

I would greatly love to hear reader feedback of this issue.....

To UPS or not to UPS?

With the warmer weather on the approach in the next few months in this
part of the world along with it comes those wonderful thunderstorms.
These often leave regions blacked-out without power for varying lengths of
time and naturally our servers and computers are out of action - crashed
out by power loss.

One of the best approaches to ensuring your server can be shutdown
gracefully without the risk of system/file damage during these times is
to put the server on a UPS (Uninterruptible Power Supply). The UPS will
maintain the power long enough for you to shut it down manually or in the
case of intelligent UPS models the server will be shutdown by interactive
software - these UPSs are usually conntected to the server via a serial
or network connection and the software does the rest.

I have worked with UPS connections to SCO and Linux systems for many years
and it is mandatory having a UPS connected to them for times of erratic
mains power. Intelligent UPSs ship with a CD containing the required
software for various operating systems and my recommended approach for
UNIX/Linux systems is to still use the serial COM port connection to the
UPS - to allow the UPS to communicate with the UNIX/Linux system to shut it

A UPS also has the advantage of being a power filter so it can protect
servers against power fluctuation damage.

UPSs range in price from as low as $160.00-$3000.00 with varying
features (uptime longevity, rack/non-rack, watts etc) but for an average
server in this part of the world around $500.00 excluding GST will get you
a good robust UPS with interactive shutdown.

Newsworthy Items

Just to save you too much surfing, some news items to note on UNIX/Linux.

1. SCO City to City Tour is about to commence and will be holding a morning
session in Brisbane on Tuesday 19th October at the Mercure Hotel, 85
North Quay, Brisbane.

Highlights will include :

Announcement of Project Diamond, the future of SCO UNIX
Extended SCO OpenServer and SCO UnixWare roadmap updates,
SCO's 64 bit UNIX strategy
New HP SAN support announcements on SCO UNIX
SCO Web Services Substrate - web service enabling legacy applications
SCO Smallfoot - the powerful and flexible SCO UNIX solution for
embedded devices
SCO hardware and database certification update.
Updates on the new SCOoffice Server 4.1 e-mail solution

2. SUN Microsystems announce a breakthrough filesystem in Solaris 10 - ZFS,
the dynamic new file system in Sun's Solaris 10 Operating System which
meets the file system needs of everything from desktops to data centers.
Designed with the administrator in mind, ZFS is the only self-healing,
self-managing OS file system.

3. Red Hat took home two Product Excellence awards at last month's
LinuxWorld Conference & Expo. Red Hat Application Server won Best
Application Platform or Development Tool. Red Hat Global File System won
Best Clustering Solution.

4. September 24th - Mandrakelinux 10.1 - The power-user version of
Mandrake linux 10.1 is now available for public download. Many FTP mirrors
are ready.

5. Cyberguard's WebWasher Prevents Microsoft Jpeg Exploit - Content
Management products filter files for malicious code regardless of
file extension.
As reported last week, hackers are scheming about how to exploit the latest
announced vulnerability in a number of Microsoft operating systems and
applications, including Microsoft Office and several versions of Internet
Explorer. The newly reported weakness allows malignant JPEG images to
enter users' computers undetected via e-mail, Web site and instant message
downloads, enabling an attacker to gain control of the computer. CyberGuard
Corporation (Nasdaq:CGFW), the technology leader in network security, prevents
attacks that might leverage the imaging vulnerability with its Webwasher
Content Security Management (CSM) solution.

Tech Tip

System performance command line based checking utilities: coming from the
traditional UNIX background I tend to still use the sar utility to
analyse how a system is performing:

sar -r 2 2
sar -d 2 2
sar -u 2 2
sar -q 2 2

all give you reports on RAM, Disk and CPU/Process throughput which help
you identify system bottlenecks. If you don't have sar on your linux
system you will need to install the "sysstat" package to get sar running.

You can also install and run products like "top" which give you a live
view into the process table itself and what processes are up to.

Many years ago a product called "u386mon" was developed and made its way
onto SCO servers around the world. To date I use "cpqmon" which was
developed for Compaqs based, on u386mon, but I have found it runs on most
hardware platforms very well.

There are many more out there but with good old "sar" and a few GNU
utilities, you can effectively diagnose your server.

Back to Newsletters

Website design by Davrom Consulting Pty Ltd
This site is fully tested with Google Chrome and Firefox web bowsers

Home Page | Support | Misc | David's Pages | Podcasts | Contact Us | Blog