Louwrentius

Ubuntu is based on Debian Linux. As part of a regular Debian installation, you can choose to create an encrypted disk volume based on LUKS. This is different from the option within the Ubuntu installation to encrypt home directories. To be able to install Ubuntu and use full disk encryption, you need to download the alternate install CD / DVD. Only this version of Ubuntu supports LUKS as an installation option.

You will have either two options:

1. use the default choice, creating a swap partition, boot partition and the encrypted root file system on top of LVM;

2. create separate crypted partitions yourself manualy.

Personaly I don't care for separate partitions and use the provided automatic option. If you do care, please read this blog for more info.

disk-encryption/

Scanning a large number of hosts using Nmap often takes a lot of time. During this time, no output is written to a file or disk. Only when Nmap is finished, is all output written to the output file. Often, I want to start processing results of hosts that have already been scanned. Often, the trick is to split the input file with all the hosts and start multiple Nmap instances by hand using the different input files. This is rather cumbersome. Now what I really want is that I get the results of a scan of a particular host immediately available as soon as it's finished. Here is where PPSS comes in. PPSS can start Nmap scans and proces a list of hosts as contained in an input file. PPSS will only start a predefined max number of simultaneous scans in parallel, as not to overwhelm the scanner, network or target hosts. This is an example on how PPSS can be used to obtain results immediately:

./ppss -f hosts.txt -c 'nmap -n -v -sS -A -p- -oN "$ITEM" "$ITEM"' -p 4

Where hosts.txt contains IP-addresses, networks or domain names like:

192.168.0.1

192.168.0.2

192.168.0.3

192.168.1.1-254

www.google.nl

The 'ITEM' part is the fun bit. In this example, multiple instances of Nmap will scan a single hosts. The output is written to a file called "$ITEM", which is of course substituted for the IP-address or domain name as read from hosts.txt. The second "$ITEM" is the argument to Nmap which tells which host to scan. The -p 4 option tells PPSS to run 4 nmap scans simultaneously at all times.

You will end up with a large number of output files, one per host. As soon as a scan is finished on one host, you can start processing the results, instead of waiting for that big scan to finish.

I had to replace my Coolermaster PSU and after some searching on the interweb, I chose the Corsair CMPSU-750HX. One of the reasons is that Corsair states that this PSU can withstand 50 degree Celcius in continuous operation on full load.

The package is very, clean, with all the cables in some neat pouch and the PSU itself also in a neat bag. You pay quite some money, but it at least suggest quality. The modular design with the modular kables is excellent.

Personally, I think that PSUs with multiple 12v rails are not that usefull. This particular PSU has just one single 12v rail that can be loaded up to full capacity of the PSU. I think this makes the design easier and if you are running heavy systems that have short spikes (starting al drives) this is ideal.

I hope this one lasts longer.

So I was just messing around on my work station, when suddenly I smelled the smell any person familiar with electronics fears. The smell of some electrical component burning.

The whole upper floor smelled like something was smoldering. So I shut down both my storage servers. After half an hour I still hadn't found the source of the smell, but it definitely was my 18 TB NAS.

So I switched it back on to see if I could determine the cause. The smell became stronger and within the strike light of my flash light, I saw small strands of grey smoke slowly twirling out of the Coolermaster Silent Pro M 600W power supply.

That was the moment I decided to turn the system off immediately. I know this kind of thing can happen. But it is still very bad for such a component to crap out on me like that.

Needless to say that I don't want a replacement of this model in my server. I will now try my luck with the Corsair CMPSU-750HX 750Watt PSU.

Based on a single experience it cannot be concluded that this Coolermaster PSU is a bad one that should be avoided. But the only moving part of a PSU is the (big) fan. What must be wrong with it that it decided to start smoking?

For reasons of availability, a redundant power supply should be used, but that is just too expensive for my taste ($500+).