Back to Newsletters 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. Back to Newsletters 
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