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Wednesday, November 7, 2007

My new Mac OS X

It has been a short while since I posted. For a while there I was without a computer. My Windows box had decided I needed an updated video driver. Last time it did this I was reduced to 320x200 16 colour graphics. This time it just totally puked my machine. I tried booting in safe mode; everything appeared to start okay but after all the drivers loaded, it switched to the Windows XP splash screen (just before the login dialog) and hung there. Booted the thing with a Dr.DOS CD I created (just for such an emergency). The registry had been corrupted.

Decided now was the time to buy a new computer. Had been looking at the Mac for a while. It is really a UNIX box with an Apple GUI. The thing makes as much noise turned on as it does turned off. The Windows box sounds like a jet taking off in the distance. I connected my ethernet cable, powered it up and it immediately found the DSL modem, knew what kind of protocol it used, asked me two questions (username and password for my ISP) and bang I was on the net.

The really cool thing is I don't have to install something like Cygwin to do Bourne shell scripting. The REALLY cool thing is what I can do without much knowledge of UNIX command line. There is a utility on the thing called 'Network Utility'. You go to Spotlight (Command-Spacebar) and enter 'network'. The first thing it finds is the Network Utility.

A lot of the stuff on this is pretty easy to use from the command line, e.g. netstat or ping. But there is a feature labeled 'Port Scan'. This thing is like nmap but a lot easier to use. You give it the name or IP address of a machine and it will probe the machines ports. It will see if something is at each port and figure out what that something is. You might thing, it sees something at port 80 and assumes it is http but I've put an application server at a different port and it found it.

I'm scanning a site now and seeing that they have turned off telnet (I think it is a Linux machine so telnetd is off by default) but they have sshd running on the standard port 22. It is a web site so no surprise there is an httpd running on port 80.

It is not clear where this thing has a passive mode (or if it is always in passive mode). I'm going to guess it is not and the host I'm probing sees me peeking at all the ports. If you want to do some stealth probing, this is probably not the tool for you. You'd have to go for command line.

Makes me wonder, why would you want this? Your average joe user can find you are running iiop on port 3528. This will mean nothing to them. Most the people who know about this sort of stuff, know command line utilities like nmap. Still, kind of fun to play with.

The typical UNIX or Linux start does not apply to the Mac. After the initial rc.d everything is started by a launchd application. Additionally, things you run from the GUI are run very differently then on say SuSE Linux. A GUI application has the elaborate structure and there is a special program that runs the application. For example, if the GUI indicates Foo is an application in /homes/darrell then to run it from the command line I'd have to issue: "/System/Library/Frameworks/Carbon.framework/Versions/A/Support/LaunchCFMApp /homes/darrell/"

The is what you see as Foo from the GUI. You don't see the Contents folder or anything else inside the directory.

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