Greylisting for the win!

I’ve seen a dramatic drop-off in email spam since implementing a greylist program a couple of months back.   As odd as it may sound, greylisting works by initially rejecting all new incoming email with a response indicating a temporary rejection.   A “real”, legitimate mail server will retry sending the email after a few minutes.   A spam-generating virus program running on a hijacked computer generally will not.   As a result, nearly all spam email just simply goes away…   and none of the “good” mail gets lost.

The system keeps track of senders that have successfully delivered mail, and adds them to a whitelist of “known good” senders so that future mail from those senders doesn’t get delayed.

This system has allowed me to retire a very long list of filter rules to try to catch spam.   The amount of time I have to spend dealing with it has dropped from a couple of hours per week to a few minutes per week.   It’s not perfect — but then, nothing is.   My employer spends tens or hundreds of thousands of dollars on anti-spam technology, and I still seen one get through every once in a while.   For zero cost and near zero hassle, this works pretty well.


Just too cool.

I was using my new-ish Owon DS7102V scope tonight to troubleshoot a problem with a PicoKeyer firmware function.  After I got it fixed, I took a screen shot to show just how impressive the capture buffer is on this thing…

Yes, that’s “DE N0XAS” in Morse code, sent at maybe 15 WPM.  I set the scope up for single-shot capture, then saved the screen image to a USB drive.  Suh-weet.  I don’t think I posted these before, but here are some from when I was testing the ID-O-Matic II audio.

The first shows the audio wave form — a nice approximation of a sine wave.  The second shows the scope’s FFT function, with two cursors (the vertical purple lines) showing the fundamental at 800 Hz, and the second harmonic at twice that.  The third shows the cursors, now horizontal, showing that the second harmonic is about 33 dB down from the fundamental.  Again…  suh-weet.  Not at all bad for a sub-$400 scope.

Removing slashes from Word-generated PDF file bookmarks

This has been bugging the hell out of me for a while now.  I write my user manuals in Word 2007, and export them as PDF files for inclusion on the HamGadgets web site as well as on the CD-ROMs I ship with each order.

Once in a while, I get an extraneous slash character in the PDF file bookmarks.  This always happens on a page where I have a diagram or picture embedded.  For example, this time it was the page of the ID-O-Matic manual that has the schematic diagram.  I could play around with moving the picture, etc — sometimes I could make the problem WORSE, but never better.  One time it showed up with a completely new bookmark, just a slash on a line by itself, which took me to the picture — not the page heading.  Eureka.

Turns out — your embedded picture can have text format attributes set, just like text can.  The picture in question got added with a “Heading 3” attribute, which made it show up in the PDF bookmarks.  Since it was a picture with no text, it jsut had a slash for the bookmark.  Depending on exactlyhow things were laid out, it could show up either prepended to the heading (like “/Schematic“) or on a line all by itself.  I imagine it would have probably shown up in the TOC if I’d added one.  I selected the picture, hit the Normal text format button, re-saved as PDF…  end of problem.

Word Help was useless, as usual, and Google searches for this turned up almost nothing.  There was a post to a M$ Office forum from someone in Holland with the exact same problem, posted in 2010 and with no replies posted.  I’m not going to sign up to that forum so I can “necropost” the fix, but maybe this blog entry till get indexed and save someone else some trouble.


Killing annoying search engine customizations in Firefox

I’m pretty satisfied with Linux Mint, for the most part.  However, one thing does bug the hell out of me — their “branding”.  Listen, if you want to make my desktop background a cute little Mint logo, fine.  I don’t care.  But when you start screwing with the Firefox search bar and sending me to some oddly-formatted, mint-filtered search page, something has to change.

Fortunately it’s not difficult.  Just delete one file and edit a couple of others…

rm /etc/linuxmint/adjustments/15-mint*firefox*
vi /usr/lib/firefox-addons/searchplugins/google.xml
vi /usr/lib/firefox-addons/searchplugins/en-US/google.xml

In the two XML files, you’ll see the customizations that send you to the Mint customized page.  When you finish, the tail end of the file should look like this:

<Url type=”text/html” method=”GET” template=””>
<Param name=”q” value=”{searchTerms}”/>
<Param name=”ie” value=”utf-8″/>
<Param name=”sa” value=”Search”/>

Kill and restart Firefox, and your search should be back to normal.

Mint Linux is the new hotness, I guess.

After a few days with Fedora16, I’d had it.  I’m sorry, btu the new Gnome 3 interface is just unusable.  Maybe if you want your desktop to be just as horrible as an iThingie…  but as a desktop, it’s just unusable.  Yeah, I read about “change your workflow” and all that nonsense.  Excuses for a really, really poor user interface.  I shouldn’t have to completely change the way I work to make my desktop happy.  It kind of sucks, because I’ve been happily using Fedora for years.  But, after all this time they managed to find a way to chase users off.

I’ve never been an Ubuntu fan, and CentOS just doesn’t do it for me.  I made that mistake twice, and one of them I’m still living with.  Not again.  So I decided to try Mint Linux.  Mint is a Debian distro, like Ubuntu, so I’m learning to live yum-lessly, but at least I can use the desktop UI like a normal computer.  It’s still not perfect.  For example, if you drag a window’s top bar too close to the top edge of the screen, it “snaps” to the top and assumes you really wanted to FULL SCREEN your Gedit note pad, not just slide it up out of the way a little.  Urk.  I can’t find a way to turn that irritating little quirk off.  I’m also not terribly impressed with the cutesie workspace switching, but I don’t use it often enough to be an issue.  So, Mint for the win — for now.


Fedora 16 released (and Gnome3 sucks).

Fedora 16 has been released as of, I think, yesterday.  I’d give it a mixed review, if not downright negative.

I upgraded my Fedora 14 system in the office to 16 yesterday using preupgrade.  The upgrade went relatively smoothly — thought for some unfathomable reason, it didn’t bother to install the new kernel.  The result was a system that took forever to do anything, was running the cooling fans flat out, and failed miserably to give me a working desktop.  once I noticed it was still running a 2.x.fc14 kernel, I had to reboot in single user mode, install the new kernel and fix grub.conf.

The biggest loser here is Gnome3.  While it’s visually kind of nice on the surface, it seems a lot of change simply for the sake of change…  and none of it good.  It’s actually much less convenient and less easy to use than Gnome2.  For example, I no longer have the drop-down menu structure for starting apps.  Now there’s an “Activities” link in the top right corner.  Any time I want to start a new application, I click that — and it rearranges my desktop, shrinking my running windows down to tile them on screen, while popping up a short bar of frequently used apps.  Or, I can click another word on the screen and see ALL of my apps, all at once, alphabetized.  No grouping, of course.  Oh – wait!  There are the groups, clear the hell on the right edge of the screen.  Why?  Did we move to Iraq or something?  Left to right, folks.  It’s almost as if they want to make Linux look like an iPhone or Android, which works OK (kind of) on a  phone sized screen but definitely not on a 1600×900 monitor.

Gone are the admin Settings menus.  How do I set video card resolution and color depth?  Beats the hell out of me.  Apparently it doesn’t want to let me log in as root now, either…   a choice that has always been MINE to make, not someone else’s.  I had to do a Google search, then edit two files to get that back.  My bottom screen bar is gone; minimizing windows makes them disappear completely, and you have to go through the stupid application click dance to see them.  Stupid, stupid, stupid.

I’m hoping they haven’t irreparably broken the “fallback mode”.  I’m switching to it.  Gnome3 is a loser in so many ways I’m not wasting any more time with it.


Another WordPress hack

This time some jackass(es) uploaded changes to several popular WP plug-ins that provided back door access to servers on which they were installed. Yet another reason to assume control of (and responsibility for) your own systems. I also try not to jump immediately on new updates of plugins and new software versions. The way I figure it, your chances of updating to a hacked version of something is reduced dramatically if you wait a few days or weeks after an update is released. It’s one reason I like to be informed of available updates, but not automatically have them installed — and I don’t want to be nagged (Avast, Adobe, Nikon…).