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Welcome to my blog, which was once a mailing list of the same name and is still generated by mail. Please reply via the "comment" links.

Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

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Lepl parser for Python.

Colorless Green.

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SVG experiment.

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Calibration of seismometers.

Data access via web services.

Cache rewrite.

Extending OpenSSH.

Last 100 entries

Sentidos Comunes (Chilean Online Magazine); Hilary Mantel: The Assassination of Margaret Thatcher - August 6th 1983; NSA Interceptng Gmail During Delivery; General IIR Filters; What's happening with Scala?; Interesting (But Largely Illegible) Typeface; Retiring Essentialism; Poorest in UK, Poorest in N Europe; I Want To Be A Redneck!; Reverse Racism; The Lost Art Of Nomography; IBM Data Center (Photo); Interesting Account Of Gamma Hack; The Most Interesting Audiophile In The World; How did the first world war actually end?; Ky - Restaurant Santiago; The Black Dork Lives!; The UN Requires Unaninmous Decisions; LPIR - Steganography in Practice; How I Am 6; Clear Explanation of Verizon / Level 3 / Netflix; Teenage Girls; Formalising NSA Attacks; Switching Brakes (Tektro Hydraulic); Naim NAP 100 (Power Amp); AKG 550 First Impressions; Facebook manipulates emotions (no really); Map Reduce "No Longer Used" At Google; Removing RAID metadata; New Bike (Good Bike Shop, Santiago Chile); Removing APE Tags in Linux; Compiling Python 3.0 With GCC 4.8; Maven is Amazing; Generating Docs from a GitHub Wiki; Modular Shelves; Bash Best Practices; Good Emergency Gasfiter (Santiago, Chile); Readings in Recent Architecture; Roger Casement; Integrated Information Theory (Or Not); Possibly undefined macro AC_ENABLE_SHARED; Update on Charges; Sunburst Visualisation; Spectral Embeddings (Distances -> Coordinates); Introduction to Causality; Filtering To Help Colour-Blindness; ASUS 1015E-DS02 Too; Ready Player One; Writing Clear, Fast Julia Code; List of LatAm Novels; Running (for women); Building a Jenkins Plugin and a Jar (for Command Line use); Headphone Test Recordings; Causal Consistency; The Quest for Randomness; Chat Wars; Real-life Financial Co Without ACID Database...; Flexible Muscle-Based Locomotion for Bipedal Creatures; SQL Performance Explained; The Little Manual of API Design; Multiple Word Sizes; CRC - Next Steps; FizzBuzz; Update on CRCs; Decent Links / Discussion Community; Automated Reasoning About LLVM Optimizations and Undefined Behavior; A Painless Guide To CRC Error Detection Algorithms; Tests in Julia; Dave Eggers: what's so funny about peace, love and Starship?; Cello - High Level C Programming; autoreconf needs tar; Will Self Goes To Heathrow; Top 5 BioInformatics Papers; Vasovagal Response; Good Food in Vina; Chilean Drug Criminals Use Subsitution Cipher; Adrenaline; Stiglitz on the Impact of Technology; Why Not; How I Am 5; Lenovo X240 OpenSuse 13.1; NSA and GCHQ - Psychological Trolls; Finite Fields in Julia (Defining Your Own Number Type); Julian Assange; Starting Qemu on OpenSuse; Noisy GAs/TMs; Venezuela; Reinstalling GRUB with EFI; Instructions For Disabling KDE Indexing; Evolving Speakers; Changing Salt Size in Simple Crypt 3.0.0; Logarithmic Map (Moved); More Info; Words Found in Voynich Manuscript; An Inventory Of 3D Space-Filling Curves; Foxes Using Magnetic Fields To Hunt; 5 Rounds RC5 No Rotation; JP Morgan and Madoff; Ori - Secure, Distributed File System; Physical Unclonable Functions (PUFs); Prejudice on Reddit

© 2006-2013 Andrew Cooke (site) / post authors (content).

IntelliJ Idea

From: "andrew cooke" <andrew@...>

Date: Sat, 31 Mar 2007 23:54:17 -0400 (CLT)

I am switching from Eclipse to IntelliJ Idea.  I have no idea whether this
will work out, but I was tired of Eclipse crashing and Codehaus have a
licence for Idea.

First impressions are that the two are generally quite comparable.  While
running checkstyle doesn't crash Idea like it does Eclipse, it does
occasionally fail on a stupid classloader problem.

However, there is one significant advantage to Idea which has impressed me
- its default analysis of code is intelligent and useful.  It flags real,
important issues rather than "nitpicking details".  In other words it
focuses more on semantics and less on syntax - it's like having an
intelligent code reviewer.  The intelligence doesn't extend to
architectural issues, but it does "understand" basic logic and flow
control.

I'm using the preview releases available from http://www.intellij.net/ -
they have a free 30 day trial licence, low price academic and free
opensource licences.

Andrew

PS It is only after writing this (I promise!) that I realise this
"intelligent analysis" may be why it's called "IntelliJ"...

Maybe Intelligent is the Wrong Word

From: "andrew cooke" <andrew@...>

Date: Sun, 1 Apr 2007 10:01:23 -0400 (CLT)

Hmmm.  My previous post was rather enthusiastic.  The advice is not
particularly "intelligent" - it's just based on simple static analysis. 
Maybe what *is* intelligent is the interface design, or the selection of
warnings.  Somehow it is useful, rather than annoying.

Another nice feature - maybe this was possible in Eclipse - is that I can
configure code highlighting in some detail.  So my text is simple black
(keywords in bold), but with mutable state (class and instance variables,
and also reassigned local variables or parameters) highlighted.

Andrew

IntelliJ Idea uses some odd ports...

From: "andrew cooke" <andrew@...>

Date: Mon, 2 Apr 2007 21:22:07 -0400 (CLT)

Don't like this much.  Idea is using the following ports:

tcp :::63342              :::*               LISTEN
tcp :::2864               :::*               LISTEN
tcp :::6942               :::*               LISTEN
tcp 200.120.169.16:16139  63.246.23.202:5222 ESTABLISHED
udp 10.2.0.1:1672         :::*
udp :::9876               :::*
udp :::2863               :::*
udp :::2863               :::*

where 10.2.0.1 and 200.120.169.16 are local addresses to my server.

Surreally, connecting via HTTP to 63.246.23.202 gives an empty page with
the title "Dick's Sporting Goods Bragging Board" (see related address
http://braggingboards.dickssportinggoods.com/)

And port 2863 regularly broadcasts "Anybody out there" to other odd
addresses.

The established link is Jabber - my machine (the editor) is making a
series of "Jabber Request" messages.

WTF?!

In related news, SuseFirewall doesn't block outgoing connections, and
Novell's AppArmour scares me.

Andrew

How to block IntelliJ Idea on SUSE (and Linux in general)

From: "andrew cooke" <andrew@...>

Date: Mon, 2 Apr 2007 21:56:21 -0400 (CLT)

OK, so on SUSE you need to go to the sysconfig editor in Yast (System
menu) and edit the firewall setting FW_CUSTOMRULES to include the custom
rules file.  Then edit that file to include the following in the first
function (fw_custom_before_antispoofing).

For other Linux distros, the same iptables commands apply but you need to
work out how best to set them.

# mess with intellij

iptables -A OUTPUT -p tcp --dport 5222 -j LOG --log-level warn \
  --log-prefix "BLOCKING INTELLIJ: "
iptables -A OUTPUT -p tcp --dport 5222 -j DROP

iptables -A OUTPUT -p tcp --dport 2864 -j LOG --log-level warn \
  --log-prefix "BLOCKING INTELLIJ: "
iptables -A OUTPUT -p tcp --dport 2864 -j DROP

iptables -A OUTPUT -p tcp --dport 6942 -j LOG --log-level warn \
  --log-prefix "BLOCKING INTELLIJ: "
iptables -A OUTPUT -p tcp --dport 6942 -j DROP

iptables -A OUTPUT -p udp --dport 2863 -j LOG --log-level warn \
  --log-prefix "BLOCKING INTELLIJ: "
iptables -A OUTPUT -p udp --dport 2863 -j DROP

iptables -A OUTPUT -p udp --dport 9876 -j LOG --log-level warn \
  --log-prefix "BLOCKING INTELLIJ: "
iptables -A OUTPUT -p udp --dport 9876 -j DROP

Note that the backslashes are not valid syntax - I added them above to
make the lines shorter in this email.  It's not clear to me that all the
above are needed, and I am assuming that you already block *incoming*
connections, but the above is the right idea (and does block several
outgoing connection attempts on my machine).

Andrew

re: IntelliJ Idea

From: "andrew cooke" <andrew@...>

Date: Wed, 16 May 2007 20:13:58 -0400 (CLT)

---------------------------- Original Message ----------------------------
Subject: re: IntelliJ Idea
From:    "Alexandre Paterson" <alexandre_paterson@...>
Date:    Mon, May 14, 2007 8:12 pm
To:      compute@...
--------------------------------------------------------------------------

Hi Andrew,

I was very happy to find your message
about IntelliJ using some strange ports...
At first I thought my machine was compromised.
However at it is a strenghtened Unix machine
behind several firewalls (the machine as its own
firewall in addition to another firewall... And it is
NATted behind a router) so I would very surprised
if it was compromised.

The UDP on port 2863 is a multicast on the LAN:

http://whois.domaintools.com/239.203.13.64

It may be followed by TCP access on 2864 and up, depending
on how many IDEA machines you have.

I was baffled too then by the attempt to connect to

63.246.23.202

A reverse IP shows that "intellijoin.org" shares that IP.

http://www.domaintools.com/reverse-ip/

Things get stranger:

 $ telnet intellijoin.org 80
Trying 63.246.23.202...
Connected to intellijoin.org.
Escape character is '^]'.
GET / HTTP/1.0\nAccept: */*\n\n

HTTP/1.1 503 Service Temporarily Unavailable
Date: Tue, 15 May 2007 00:03:04 GMT
Server: Apache/2.0.52 (Red Hat)
Last-Modified: Tue, 05 Sep 2006 15:38:54 GMT
ETag: "269405-31c-a7f01f80"
Accept-Ranges: bytes
Content-Length: 796
P3P: CP="PHY ONL CAO CURa ADMa DEVa TAIa PSAa PSDa IVAo IVDo CONo HISa
TELo OTPo OUR DELa STP BUS UNI COM NAV INT DEM
OTC",policyref="/w3c/p3p.xml"
Connection: close
Content-Type: text/html; charset=UTF-8

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>
<head>
<title>Dick's Sporting Goods - Bragging Board</title>


But if you type www.intellij.org in your browser everything
is fine: you get to a site obviously belonging to JetBrains.

I'll post a message in the IntelliJ IDEA forum asking
what is going on.

Anyway... Instead of blocking things I want to be blocked,
my system is configured to REJECT everything, even
access to 127.0.0.1.

Then I allow what I consider to be legitimate trafic.

For example, if I want IntelliJ to be able to access my
LAN Tomcat server (that has some html Javadocs,
for example), I do:

iptables -I OUTPUT -p tcp -d 192.168.2.23 --dport 80
-m owner --uid-owner 1007 -j ACCEPT

Same for SVN, CVS, JProfiler, etc.

I do it this way so closed-source programs emitting
spooky trafic are blocked in a user account (that can't
even communicate on 127.0.0.1).

This is painful with some dumbly-written plugins and
utilities that thinks that they can appropriate a great
many ports but all in all it poses no problem.

Anyway, it takes some time to set it up at first but
I honestly think it's worth it.

"Everything that is not specifically allowed is denied"

:)


Besides that upon hitting your blog (I was googling
on "63.236.202 jabber" IIRC) I recognized your blog
instantly :  I *love* your gallery.

I saw it quite some time ago and saved a few pictures.

Congratulations.




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Fwd: on blocking incoming trafic

From: "andrew cooke" <andrew@...>

Date: Wed, 16 May 2007 20:14:49 -0400 (CLT)

---------------------------- Original Message ----------------------------
Subject: on blocking incoming trafic
From:    "Alexandre Paterson" <alexandre_paterson@...>
Date:    Mon, May 14, 2007 8:21 pm
To:      compute@...
--------------------------------------------------------------------------

Re,

you wrote:

> Note that the backslashes are not valid
> syntax - I added them above to make the
> lines shorter in this email.  It's not
> clear to me that all the above are needed,
> and I am assuming that you already block
> *incoming* connections, but the above is
> the right idea (and does block several
> outgoing connection attempts on my machine).
First in a Bash shell script where you put all your iptables
rules the backslash is actually a perfectly correct syntax:
it's the one I'm using for my long iptables rules ;)

Then on a stateful firewall, you usually block *new*
incoming connections, not RELATED or ESTABLISHED
ones.

Usually people have :

iptables -I INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

which may be a problem when a rogue program decides
to establish the connection from your computer: no matter
how much you block incoming stuff, if you allow RELATED
and ESTABLISHED trafic in (which is usually how iptables
is configured), you're hosed.

To me the real best option is to "deny everything that
is not specifically allowed".

Thanks again and talk to you one of these days,






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