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Alex Belits
My mail server in Denver was running Exim 3 for at least five years. Spam filtering was done with a simple setup with Bogofilter called by a delivery agent wrapper that I wrote to avoid using large monstrosities in perl on a resources-starved server. Mail delivery agent wrapper also performed another function -- fixed non-ASCII headers before passing mail for delivery, so Cyrus won't complain about them. Filtering was done by running bogofilter on the message, checking its result and passing "-m spam" to Cyrus delivery agent if the message is supposed to go into spam mailbox. If user had "spam" mail folder under "INBOX", spam ended up there, otherwise Cyrus will put it into INBOX, but the message will still have identifying headers that mail reader can use to mark it as spam.

This had to be upgraded...Collapse )

I am running this configuration for almost a week now. The amount of spam went down at least ten times when counted before bogofilter, and spam now mostly consists of short messages containing a random phrase and a URL. Apparently long messages are all sent by botnets, viruses, and spam-specific software while short ones are usually passed through regular mail servers -- I have found what looks like signatures of Microsoft Exchange, Sendmail, Qmail and Exim in them. Bogofilter still filters most of them out, however their short size and legitimate headers make them the most difficult to filter, and I still get tens of them per day in my regular mailbox. I will see if more spammers will switch to this mode that may prompt me to add another kind of filtering specifically against that style of spam.

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Current Mood: accomplished accomplished

While XEmacs is a great text editorM-<Delete>M-<Delete>developmentM-<Delete>interactive environment, it has one problem -- its default configuration looks ridiculously ugly:

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I mean, background that reminds me of Motif defaults and NCSA Mosaic, fonts from Hell, and UI elements that look like they can fall off the screen and cause some considerable damage to my feet. With the help of the /etc/X11/app-defaults/Emacs and ~/.xemacs/custom.el its ugliness can be reduced to this:

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The custom.el file has the line about KOI8 Cyrillic environment commented out -- uncomment it if you need it. Some fonts are Monotype fonts from "corefonts"/"msttcorefonts" package -- install them or change font names to something you have.

Please note that XEmacs uses X fonts while GTK and Qt use Xft fonts -- it means, XEmacs can't use font smoothing, and you have to make sure, font is included in X server configuration (shows up in xfontsel).

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Last two entries were about the incident, and I guess, many people who had seen them, found most of the text to be unreadable technobabble. Since at this point the immediate problems are solved -- is up, and scammers lost their email addresses -- it makes sense to explain, what the hell happened, and why.
Very long entry hereCollapse )

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On August 4 I have got a call from j_b -- he had remotely rebooted box, and sshd failed to start. The box runs Debian Sarge, and is located at my lab, connected to my network to use my otherwise underutilized bandwidth, so I was the only person who could look at the console and restart sshd. The fact that sshd failed to start was not by itself suspicious because that box occasionally went through upgrades and reconfigurations, and it wasn't too much of a stretch that sshd startup script ended up in a broken state at the moment when the box was rebooted.
Cut for hugenessCollapse )

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The company bought an old IBM Infoprint 32 on Ebay -- even older Lexmark Optra E310 that was our main printer used for drawings and templates had worn out paper feeding mechanism, and 8 inches wasn't nearly enough for most of the drawings that we had to produce. Infoprint 32 supports Postscript, and prints on up to 11x17", what is kinda reasonable, considering that equipment made for 19" rack should fit into 17". The problem is, it doesn't come with a PPD file, and searching for it returns nothing.

After more searching I have found a Windows driver from IBM,, that happened to be a CAB archive. It contains, among other things, IBM43321.PPD, a file that doesn't seem to be present anywhere else. Feeding it to CUPS enabled me to print large drawings in a civilized manner, that is, without switching paper formats by pulling the Letter tray out.

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Some time ago nickhalfasleep gave me an old Alpha workstation that was too slow for its original purpose, and didn't have enough storage to be useful as a server. Separately I had a box of old 36.4G Compaq drives with SCA connectors, and SCA to 68-pin SCSI adapters. So in theory I could add a RAID array, and end up with a usable server.

Digital Workstation case modCollapse )
I realize that after all those changes it's still far behind anything modern, especially compared to things that we build now. Nevertheless it runs NFS server, and handles backups for all other boxes at my work, what makes it useful.

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We all know about dual (and multiple) head setups -- install a board that supports multiple screens, or just multiple boards, or both, connect monitors, configure X to either run Xinerama or just multiple screens (or run Ultramon if you use Windows), and you have multiple screens, that share mouse and keyboard, allowing you to move the pointer around them, more or less following their physical layout.

From that point opinions are split -- some people prefer Xinerama-like configuration where all monitors form a large screen (so a window can be simply dragged between them), some keep screens separate. There is however a situation that often happens to sysadmins -- they get a lot of equipment but it's all underpowered, and the numbers of computers remains equal to the number of monitors. The obvious solution is to just attach all video cards and monitors to the fastest computer, and from there use remote X and ssh to talk to everything else. If the "main" desktop is fast enough, everything is great, however usually this is not the case, and latency+network traffic increase make this configuration rather suboptimal.

Another solution is to simply have all computers separate, and use separate keyboards and mice for them. This would be great if not the need to keep all keyboards somewhere on the desk, plus leave enough space near each of them for the mouse (or use multiple trackballs) -- the whole setup is cumbersome even with two boxes on the average desk. To save space, one can use a KVM switch without the "V" part, however having to turn the knob every time you switch between computers is annoying, and on top of that many sysadmins, myself included, hate KVM switches with a passion, and don't want to see them anywhere close to their desk on principle.

Faced with this problem, I have decided to keep "heads" where they originally were, yet build a setup where I can do everything from a single keyboard and mouse. The program to do this magic behind the scenes is already known, it's x2x, however something still has to run it when the user still has no control over a computer without a keyboard. And it would be reasonable to expect that on multiple computers joined in this setup the user may login, logout and reboot them at different times, losing the connection between them. And last but not least, there is always a matter of security -- the times when people did not think twice before typing xhost + passed long ago.

Here is my solutionCollapse ) Update: Oh, wow, I had ssh-x2x-slave truncated for three years in this entry. Fixed.

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Alex Belits
User: abelits
Name: Alex Belits
Back November 2013
Current project
Trogdor, the 1u Athlon/Opteron server.
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