madnet.ch - Rolf Klemenz » Technology

Certified ScrumMaster

Rolf — Fri, 25 Jun 2010 16:38:39 +0000

On 21./22.6.2010 I attended the ScrumMaster Certification Training by Jeff Sutherland. It was a great experience to get first hand information on Scrum and what it really can do for your productivity. As a strong believer in lean processes, Scrum is a perfect fit.

R.I.P Sun

Rolf — Fri, 22 Jan 2010 18:41:35 +0000

James Gosling’s Blog

Setup a VPN between Mac OS X 10.5 and an iPhone over a Netopia 3346 from Bluewin

Rolf — Sun, 30 Aug 2009 12:38:31 +0000

Took me quite some time but, finally I managed to get it up-and-running: My personal VPN, connecting my iPhone and my home network. This post outlines the most important things.

Your Mac OS X has all the capabilities built-in to setup a secure VPN:

racoon (ipsec)
vpnd (l2tp/pptp tunnelling)
pppd (connection)

The only difference to Mac OS X Server is that there’s no GUI for a simple configuration.

VPN Server Set-up

There’s where iVPN comes handy.
It’s straight forward to use and self-explaining. iVPN maintains a valid configuration file for vpnd (/Library/Preferences/SystemConfiguration/com.apple.RemoteAccessServers.plist) and takes care of your chap.secrets and user.plist (both in /etc/ppp).
Versions above 2.4 cost something — but you can use the old 2.4 release (Download here)
because you only need it for the initial set-up.

The only thing to do after you created your config with iVPN 2.4 is to chmod 600 /etc/ppp/* to protect the plain text passwords.

To start your vpn, you can use either iVPN or simply call vpnd from your terminal.

Client Set-up

Now configure your iPhone to use L2TP/IPsec and run a local test on your wireless LAN. Use the same values like before… Works? Good, then proceed.

Netopia Router/Firewall/NAT Config

Put your netopia to ‘expert mode’. Goto configuration->NAT/Games.

The Netopia box needs to have the following ports forwarded to your VPN server:

Netopia Port Forwards

“L2TP” is a manual UDP Port 4500 forward
“L2TP Traffic” is a manual UDP Port 1701 forward

Now configure your iPhone to use your public IP address and try to connect.

On your VPN server you should see all activity in the log file /var/log/ppp/vpnd.log

I’ve chosen to use L2TP/IPsec because it is more secure.
PPTP is basically supported as well, but I did not get it to run and I didn’t want to spend more time on this.

VMWare aquires SpringSource

Rolf — Tue, 11 Aug 2009 06:08:24 +0000

VMWare announced the aquisition of SpringSource, which is responsible for the excellent application framework “Spring” we use for development.

TechCrunch has a good post with some more facts.

(via TechCrunch)

Laws of Software Development

Rolf — Fri, 10 Jul 2009 18:48:56 +0000

Found a pretty old but nice article collecting some laws of software development.
http://www.globalnerdy.com/2007/07/18/laws-of-software-development/

(via Global Nerdy)

Facebook to support OpenId as relying party

Rolf — Tue, 28 Apr 2009 05:20:44 +0000

Some time ago I asked myself the question, “why does Facebook not support OpenId to log in?”.

Despite the fact that facebook directly competes OpenId with it’s facebook connect product, they’re even going a step further than most of the other sites featuring OpenId logins.
Facebook seems to become not only an issuing party (make your accounts compatible with OpenId) but also a relying party (accept login credentials from other OpenId sites).

Hopefully this will help OpenId to increase popularity…

(via TechCrunch)

Oracle to buy Sun Microsystems

Rolf — Mon, 20 Apr 2009 12:16:29 +0000

Various sources report that Oracle will buy Sun Microsystems.

I’m not sure if this will make my life easier or even more complicated… (I have to deal with IBM Websphere, Sun Solaris and Oracle DBMS)

maven and canoo webtest pitfall

Rolf — Mon, 06 Apr 2009 19:47:13 +0000

Today, I spent about 2 hours to find out why our canoo webtests didn’t run anymore after adding the webDAV wagon to our maven build.

The problem was that when adding the webDAV-wagon to your build as an extension, you also get the commons-httpclient dependency to the maven runtime classpath. This wouldn’t be too bad, but the 1.0-beta2 version of the webDAV-wagon depends on commons-httpclient version 2.0.2. That’s way too old for canoo webtest and is also deprecated for almost a year now.

I found out that starting with maven 2.0.9 you don’t need to have an explicit reference to the webDAV-wagon as extension anymore.

E voilà! Suddenly it worked. Maven 2.0.9 also seems to work with version 3.1 of commons-httpclient, the same version canoo webtest depends on.

So, if you get a ‘NoSuchMethodFound’ for HttpConnectionManager.getParams() first check if you’re using the webDAV-wagon extension first.

Gallery Included

Rolf — Sat, 28 Feb 2009 08:34:49 +0000

I also included a small gallery to the site. The gallery content comes from my images server through a php script and the presentation is done using jQuery with livequery and slimbox2.

I had to use livequery because I wanted to add a lightbox effect to the asynchronously loaded DOM for the gallery content. That’s a common problem when dealing with ajax.

This is how it looks like now:


    
    
    
    
    

...
jQuery( function() {
    $("#g .gallery").livequery(function() {
        $(this).children("a").slimbox();
    });
    $("#g .galleryContainer").livequery(function() {
        $(this).click(function() {
            $(this).children(".gallery").slideToggle("slow");
        });
        $(this).children(".gallery").slideUp("slow");
        $(this).children("h3").hover(function() {
            $(this).fadeOut(100);$(this).fadeIn(500);
        });
    });
    $("#g").load("/galleryImages/AllImages.php");
});

Tuning Gigabit Ethernet on Mac OS X (10.5)

Rolf — Mon, 16 Feb 2009 08:13:24 +0000

I recently bought a new NAS (Netgear ReadyNAS Duo) and attached it to my gigabit ethernet network. Unfortunately I only got transfer rates at around 10 MB/s which is really poor. I enabled Jumbo Frames (MTU > 1500) but this didn’t help much. So I did a bit more research and found out that the limiting factor was not only the MTU but the send and receive buffers.
This means my CPU was not able to catch up with the speed of the gigabit ethernet. What I did then was to increase the send and receive buffers for TCP/UDP traffic. É voilà! Now I get at least 35 MB/s. Still not the max a gigabit ethernet can offer, but I’m on the right way. I’d like to see something like 80-90 MB/s. Given the Samsung Disk can do at least 175 MB/s to/from buffer this should be possible.

I use the following parameters in my sysctl.conf:

kern.ipc.maxsockbuf=2500000 net.inet.tcp.sendspace=1000000 net.inet.tcp.recvspace=1000000 net.inet.tcp.mssdflt=7936 net.inet.tcp.delayed_ack=0
The buffers are probably too high, I know.