Tales from the Gryphon/ archives/ 2005/

Tales from the Gryphon

Archives for 2005/05

Manoj's hackergotchi
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Monday 02 January
2006
Link: Belated ramblings on the state of the voting related stuff

Posted early Monday morning, January 2nd, 2006

Belated ramblings on the state of the voting related stuff

Well, as most of us have gathered, yet another DPL election session came to a close. The highlights from a technical standpoint this year were that Devotee was modified mid-stream to grok encrypted ballots (early encrypted ballots, though rejected, contributed by testing devotee). The other, more visible, high light was that devotee now spits out dot graphs to depict the pairwise contests in the Beat matrix, and the resulting graphical representation of the results were published. The reaction being mostly positive, I went back and punched in graphs on most of previous results that were at all complex and could benefit from the graph diagrams.

While I was changing the vote pages, I responded to criticism of the navigation panel (or the lack thereof) on the vote pages, and the result(after a couple of false starts) is aesthetically more pleasing (well, to me it is).

Hmm. Bits from the secretary ain't ever gonna happen. As this entry shows, they are deadly dull.

Manoj

Monday 02 January
2006
Link: CRM114, Spamassassin, MIMEDefang, Sendmail, MailAgent -- and GreyListing

Posted early Monday morning, January 2nd, 2006

CRM114, Spamassassin, MIMEDefang, Sendmail, MailAgent -- and GreyListing

I have been fairly comfortable with my current mail filtering solution. Unlike some other blogs on Planet, when last I was doing exhaustive checks, I had not had a false positive in six months (now I just do random spot checks). The false negatives creep up from a few a week to a few a day (with a mail feed of about 1k emails a day). And the stuff that is classified as a definite spam is REJECTed (I do keep a copy), which means that a legitimate correspondent would have an idea something went wrong (unless they are ignoring such bounces form their own MAILER-DAEMON).

Part of the reason for this satisfactory performance is that I use a layered approach, with several tools playing off each other, ameliorating each others mistakes. Admittedly, this took painful training -- I created a testcrm user, and bounced a copy of every mail I got to it using a .forward. Then, over a course of two months, I would painstakingly go over the classification, training on error, until the failure rates dropped to levels I felt comfortable with, and moved the CRM114 and Spamassassin configuration over for my own use.

I recently added a hand crafted Greylisting implementation to MIMEDefang -- in good MIMEDefang tradition, this is a heavily tweaked version of an implementation on the mailing list, using PostgreSQL. I have modified it to not greylist every single new email that comes my way, but to only greylist stuff that CRM114 and Spamassassin have been unable to classify strongly as Spam or ham. mail that has been strongly classified already, in turn, affects greylisting.

Here is the SQL code for the implementation, and the mimedefang-filter itself, showing how I integrate CRM114 and Spamassassin along with greylisting in a Sendmail Milter.

Have fun.

Manoj

Monday 02 January
2006
Link: Colour theory and colour schemes

Posted early Monday morning, January 2nd, 2006

Colour theory and colour schemes

No longer having an excuse for not creating my web site (researched a ISP, check; set up machine, check; ran through other items on the to do list; check), I natually had had to create new ones. Thus I embarked on a long process of educating myself about colour theory. It was an interesting journey. I had never understood the horse shoe shaped chart the used for colour calibrations; I have a lot to learn. And all the theory in the world does not make it easier for me to select a color scheme that does not suck.

The pages I ran into fell into four categories; those that talked about Color Theory and Physics, a very scant few that dealt with design, lots of practical web page construction sites that went into detail about color schemes and tutorials, and a bunch of math stuff. Hopefully these shall be useful to someone.

The grand culmination of all this research was a perl script that takes a color in hex notation, and generates a color report -- for example. here is a report for #DEE3FF, which is the basis for one of the themes for this page. Of course, the generated page, though very nice in telling me how I can create a color scheme based on my initial choice of a basis color, did not actually help --- since the colors initially selected clashed wildly with the graphic at the top. I had to scrap the initial choices and start over, though having the program made the process less painful than it would have been.

I need to polish up the perl script, and flesh out the descriptions of the links it creates, and perhaps add more command line options, or stuff. bling-bling is always important, especially for code.

Manoj


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