Davrom Consulting Pty Ltd

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KEYWORDS=davromspam, spamassassin, print, printserver, tcpsend, lpd, cups, netcat, synonym, sendmail, capture, postfix, exim, root, user, superuser, mailbox, vim, vimrc, syntax, Davrom Consulting Newsletter - Issue # 34 - Dated: 20 Oct 2006


From the desk of David Clark
Our website is undergoing a bit of an overhaul at the moment and the
individual newsletters links will slowly update to the new location. We
use a single shell script to update our website which simply belts all
the information into place and makes sure the latest buttons, links and
footings are set for each specific page.

Support lately has been Spamassassin installations (where did you all
come from) and we have developed a product called 'davromspam' which is a
utility that auto-archives the spam e-mails and keeps them for 30 days -
this way if there is any ham (good messages) it is easy to go back in and
retrieve them.

It also seems like the month for setting up print servers on SCO and
Linux servers. We use 'tcpsend' (like netcat) for all SCO network printers
and standard lpd/cups on Linux servers (is there any other way?).

We have also been working with interfacing the shell environment with PHP
on some servers to give you HTML/Web based solutions like a parts catalog
database, a contacts manager, a web server file uploader and heaps more.

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

David.M.Clark


UNIX Quote
Old servers never die, they just become the company's Linux Web server.


Synonym and Sendmail
For those who wish to keep a copy of all your incoming and outgoing
e-mail on your server running Sendmail, Synonym does the trick.

Synonym is a free Linux/UNIX program and comes as a gzip-tar file (for
self compiling/building) and RPM for those running servers such as
RedHat/Fedora.

You specify the local e-mail user you wish to copy all the e-mail to in
the /etc/synonym.conf file, restart Sendmail and all e-mail traffic is
captured to the e-mail users mailbox (we setup a user called grabmail).

We have developed a back-end script (much like the 'davromspam' utility
mentioned in the editorial) to auto-archive the mail files to files and
directories so the mailbox doesn't get too big - which doesn't take long
to do given it records everything.

Worth a look into if you want to keep track of your company's electronic
communications.

Note: For those who are running PostFix or Exim instead of Sendmail, this
same e-mail capture process does not require synonym as you can CC all
e-mail to a specific user by setting an entry in the config files for
these e-mail servers/MTAs (Mail Transfer Agents).

Who is reading the root user's e-mail?
One of the biggest files that I find on Linux and UNIX systems is often
the root user's mailbox. It will have e-mails from the system often
dating back to the the installation date of the server. For those not
familiar with what the root user is; this is the user that has complete
control and access to the entire system and is often called the Super
User.

Your system will generate at least one e-mail to the root user on your
UNIX/Linux server each day. The contents of which are hardly very
exciting to most, even those who just like reading e-mail, will shun
being setup to receive the root user's mail.

But it is important to at least monitor the root mailbox just to make
sure no critical error messages are being sent - hardware errors or
system backup failures may go un-detected for a long time. Most servers
that act as an e-mail server will have the root user setup as the
Postmaster on the server, hence it will get all the failed e-mails that
are not routed back to the individual user who sent them or should
receive them.

Some strategies for handling root user mail:

1. Read it - you can setup an additional POP account to download root
user e-mail or get familiar with the UNIX/Linux command line readers.
Those running a GUI desktop on the server can use products like KMail,
Thunderbird or Evolution to read e-mail.
2. Redirect it - depending on your e-mail system, you will have a
mechanism that will allow you to divert root user e-mail to a "live"
user. This is known on most systems as "aliasing".
3. Delete or null out the mailbox - although this can be done on most
quiet systems, it is well worth avoiding if possible.

From the Trenches
Some comic relief from the support days gone by.
I remember the early PCs and helping a customer over the phone trying to
get the PC to read or write to a floppy disk. This was in the days of the
1.2Mb - 5.25 inch floppy disk.

The customer had inserted the floppy disk but to both our dismay, the
PC stated it had a floppy error. The light would come on but nothing
would read and the error messages continued. In those days the floppy
disk was locked into the drive by a lever and the lever would normally
not close if a floppy was not in the drive.

The customer informed me that the floppy drive lever would not click into
place despite the floppy being in the drive - I was baffled.

I asked the customer to remove the floppy from the drive and this is where
the clue to the problem was. The customer informed me that to get the
floppy out of the drive they needed to use a pair of tweasers or plyers!

It turned out that they had been putting the floppy in between the small
horizontal slot between bottom of the actual floppy drive itself and the
rest of the machine. Needless to say from this point on we made sure when
the drives were installed we put the face plates as close as possible
together to prevent them being used as floppy slots.


Tech Tip
Ever tried to run vim and found that your colours didn't show up too
well. Especially if you have a blue background in your telnet window -
you end up with dark-blue text on a blue backgroup which makes your
text almost invisible.

The solution is to run the vim command on the file you want to edit, eg:

vim /tmp/jireh

and then press the ":" key which displays the ":" character at the
bottomw left-hand side of the screen. Here you type in the command:

syntax off

and you are back to no colour enforcements and you should now have a
working colour scheme you can at least see.

To make this permanent you place the command "syntax off" in a file in
your HOME directory called .vimrc.


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