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Ralsina.Me — Roberto Alsina's website

Playing with literate programming

I am us­ing ra-­plu­g­ins as a toy to do things I nev­er both­ered in oth­er project­s.

I am do­ing unit-test­ing. And now... some lit­er­ate pro­gram­ming!

Ok, not much, and not very well, but at least I am play­ing with Lp4all which is a nice, sim­ple tool to gen­er­ate nice HTML from slight­ly wik­i-­marked sources.

You can see some lit­tle things in my code here. My vere­dict so far? A nice way to keep the code doc­u­ment­ed in a fash­ion that ocasi­nal browsers can fol­low.

The main thing miss­ing is au­to­mat­ic cross-ref­er­enc­ing.

In gen­er­al, I am find­ing that this (and unit test­ing) helps me ex­press ex­plic­it­ly to my­self what the heck I am try­ing to do, and see if the code ac­tu­al­ly does it. Which is a re­al­ly good thing.


Ok, the SPF im­ple­men­ta­tion sit­u­a­tion is kin­da pa­thet­ic.

There seems to be ex­act­ly one main­tained C im­ple­men­ta­tion. And it's win­dows-on­ly.

  • lib­spf's we­b­site seems to have dis­­ap­­peared

  • lib­spf2's not RFC-­­com­­pli­ant (ver­i­­fied for 1.2.5) and their is­­sue re­­port­ing sys­tem bounces.

So, I have tak­en the most com­pli­ant one I found whose code I can ac­tu­al­ly fol­low (that would be the python one) and am reim­ple­ment­ing it in C (us­ing bstr­lib and lib­d­jbdns).

It will prob­a­bly not come to a good end, but hey, it may work ;-)

There is one thing worse than not having a test suite

UP­DATE: There is *an­oth­er* *bet­ter* test suite It is in YAM­L, though, so I need to parse it be­fore I can use it, but that's my prob­lem.

It's hav­ing a test suite that makes no sense.

I have writ­ten, for my ra-­plu­g­ins project (y­ou don't have to know what it is for this post any­way) a piece of code that tries to check mail senders us­ing SPF.

SPF is an open stan­dard. It has stan­dard im­ple­men­ta­tion­s. It has a test suite (http://www.schlit­­s/).

The test suite says this:

spf­query -ip= -sender=05.spf1-test.­mail­zone.­com -h­elo=05.spf1-test.­mail­zone.­com re­sult /.*/ fail smt­p-­com­ment /.*/ ex­pla­na­tion head­er-­com­ment /.*/ spf­query: do­main of 05.spf1-test.­mail­zone.­com does not des­ig­nate as per­mit­ted sender re­ceived-spf /.*/ Re­ceived-SPF: fail (spf­query: do­main of 05.spf1-test.­mail­zone.­com does not des­ig­nate as per­mit­ted sender) clien­t-ip=; en­velope-from=­post­mas­ter@05.spf1-test.­mail­zone.­com; helo=05.spf1-test.­mail­zone.­com;

So, yeah:

$ spfquery -ip=
Please see
spfquery: domain of does not designate as permitted sender
Received-SPF: fail (spfquery: domain of does not designate as permitted sender) client-ip=;;;

So, the stan­dard im­ple­men­ta­tion does what the test suite says.

Too bad that, if you both­er check­ing the URL you are told to "please see"...

The do­main 05.spf1-test.­mail­zone.­com has pub­lished an SPF pol­i­cy, how­ev­er the pol­i­cy is neu­tral on whether is au­tho­rized to send mail on its be­half.

Ei­ther both the test suite and the sam­ple im­ple­men­ta­tion are wrong, or the site is wrong. And I am lean­ing to­wards "the test suite is wrong", be­cause...

$ host -t txt descriptive text "v=spf1 default=deny"

If you check the record syn­tax (­­tax) de­fault is an un­known mod­i­fier, and should be ig­nored, so the record is sim­ply "v=spf1", and in­deed the re­sult is neu­tral and there is no rea­son why this should be a fail.

My qmail-courier-whatever munin plugins

A few peo­ple have asked me for the code. Ok, here it goes.

First, get qm­rt­g.

Then you need this: qmunin.­tar.bz2

Then build and in­stall it. You may need to mod­i­fy the sources, de­pend­ing on just how your qmail work­s. There are some ex­am­ple munin plug­ins in­clud­ed (in span­ish, I am not trans­lat­ing them ;-), which 99% sure­ly will not work for you, but they are sim­ple shell script­s, so you should be able to hack them.

Cre­at­ing a re­al re­lease of this is just use­less, be­cause ev­ery­one's qmail logs look dif­fer­en­t, so take it and hack it.

And that's it.

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