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Introducing DHCP Failover in Windows Server 2012

Windows
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One of the most central feature there is within a private network, not depending on size or architecture, is DHCP. Until today Windows server was not able to have a failover feature implemented, only exception was to include the feature in a Windows failover cluster. But not anymore: it became a feature in Windows server 2012. Of course it only runs on Windows server 2012 so you will have to upgrade your two servers first which will hold the two DHCP roles. After you successfully upgraded: 1. Install the DHCP role on the server1 and set up the first DHCP server according to your needs. Authorize the server and create your DHCP scopes. 2. Switch onto the server2 and install the DHCP role as well. Authorize the server. 3. Switch back onto server1 and right-click “configure failover” (IMAGE) 4. When asked for partner server enter the FQDN of server2 and click “Next” 5. Give the relationship a name, enter a shared secret for the relationship to use and click “Next” 6. Leave settings for MCLT*, change operation mode to “hot standby” and finish wizard Voilà, that’s all there is to do. You’re set up for DHCP failover, do not forget to present the IP address of the second DHCP server to all your other components. For more detailed information and all powershell commands to realize this cool new feature on server core visit the following link from the Microsoft Technet: http://blogs.technet.com/b/teamdhcp/archive/2012/06/28/ensuring-high-availability-of-dhcp-using-windows-server-2012-dhcp-failover.aspx   Picture: http://technet.microsoft.com   *Definition of MCLT (Technet): The Maximum Client Lead Time (MCLT) is additional time provided to a DHCP client...

Logon credentials issue after Windows 8 upgraded to 8.1

Windows
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When setting up Windows 8 I decided to create a local user, I’m not a big fan of the live ID. The live ID is mandatory for the store, but if you don’t use the store the live id is mostly useless. Microsoft really does not need to know everything, we have Google for this. Anyway, after upgrading to Windows 8.1 I was a bit surprised that I had to log on to my Windows with my live ID again. And surprisingly I was not able to change back to my locally created user. This was an absolute no go and after some search I found a work around from a member of the technet. Follow this procedure to disconnect from your windows live id to get back onto your local account: Move your mouse to the upper right corner, click on settings, then change PC settings Select accounts in the left menu Below your windows live account click disconnect This opens a box giving you the opportunity to log on to your local account again. If you don’t have upgraded yet you can avoid this from happening by unplugging your network connection. Also you have the opportunity to create a local user when setting up windows 8.1 from...

The techie blogger says hi…

General
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Hi, I’m the new guy… My name is Alan, I’m 31 years old and work as a system engineer. Most of my work is about Windows and VMware, so those topics will mostly be covered by me. Also I will help Guy to write about new infrastructure topics and I may even add a little Android segment when there’s something interesting to mention once a while. So I hope you will enjoy what I have to tell the world and feel free to contact me or comment on my post...

Alan: New author at guylabs

General
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Hi today I want to introduce you a former study colleague and a good friend: Alan. Lately he asked me if I turned into a "blogger" and that he also wanted to create a blog, but was too lazy to set everything up. So he asked me if he could write some techie posts on my blog, and I said yes why not. I know that he is a techie guru and some Windows things are a good contrast to the geeky linux posts  :lol: I also added his about text in the about section and I'm excited about his...

How to install fish shell in Ubuntu 13.04

Linux
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I used the fish shell for some time now and I'm really happy with it. The highlighting, the command completion etc. are great. Today I want to show you how to install it and use it as default shell in Ubuntu. Ok let's start by installing the fish package from the Ubuntu repository with the following command: If you want the newest version you can go to the developer website and download the newest .deb file for Ubuntu. Next we need to set fish as the default shell. Execute the following command, log out and login again and when you now open a shell it should show the fish shell. It's worth read the documentation about the fish shell because it's very powerful and has a lot of useful features you surely dreamed of. ...

How to fill a hard disk with zeros

Infrastructure
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This short how to shows you how you are able to fill a hard disk with zeros, such that the data can't be restored anymore. For this we use the good old dd command (https://en.wikipedia.org/wiki/Dd_(Unix)). Ok let's start by mounting the hard disk you want to erase. Then execute the following command to see which file system you want to erase: Ok after you have the desired file system (something like /dev/sdb) you need to execute the following command to fill the hard disk with zeros: This will take a while and because you don't get any output on how long it will take you can use the pv command (http://linux.die.net/man/1/pv). This tool will show a progress of the data going through the pipes you define. To use it we need to first install it: And now execute the following command to have a dd command with a progress bar: Replace the placeholder with the size of your hard disk in GB such that pv can calculate the remaining time for the process. Ok that was the short how to about zeroeing out a hard disk. Happy erasing! ...

Cisco ISA550W Review

General, Infrastructure
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Some month's ago my cheap Thomson WLAN VOIP router, which I got from my ISP, just stopped working and I needed something stable and secure. I searched a lot, read a lot of reviews until I found the ISA550W from Cisco. It had everything which I needed: Gigabit Ethernet 802.11b/g/n WLAN Integrated security appliance (ISA) And it didn't cost that much (around 360$) like a real business hardware firewall (1000$ +). There is also the greater brother of the ISA550W the ISA 570W, which just has better performance, more ports and throughput than the ISA550W, but for me the throughput was enough. Ok here now the specifications: Firewall Throughput 200 Mbps IPsec VPN Throughput 75 Mbps Anti-virus Throughput 50 Mbps IPS Throughput 60 Mbps UTM Throughput 45 Mbps Maximum Connections 15000 IPsec VPN Site-to-Site Tunnels 25 IPsec Remote Access Tunnels 10 SSL VPN Tunnels 10 Total Interface 7 GE WAN Interface 2 GE LAN Interface 6 GE WLAN (802.11b/g/n) yes DMZ Port Up to four The detailed specs you can get here and the full administration guide here. So I bought it right away and started configuring. First of all I must say that you can configure nearly everything you can imagine. (Especially when you are used to a silly Thomson router admin interface) I didn't had any problems yet with this router, but the only annoying thing is, that the security updates are just valid for one year, and then you need to renew the subscription to get updates for the anti-virus, IPS etc. Today I use the IPsec VPN, anti-virus, IPS and the standard network configs for WLAN, port forwarding etc. which all...

Avahi and unicast domains .local

Linux
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Today I want to tell you something about the .local domains when you use Avahi. At edorasware we use vSphere from VMWare to manage our virtual machines. For accessing it we need to connect first to the local network via VPN and then connect to the vShere server. Inside the vSphere application you can connect yourself to the console of each VM with a browser plugin. But this didn't work because we use the .local domains for the VM's inside the local intranet. To resolve this issue I needed to open the file /etc/nsswitch.conf and replace the following line with this one here: But there are other ways to fix that: http://avahi.org/wiki/AvahiAndUnicastDotLocal What I also saw is that when I connect to the SSH daemon via VPN it connects a lot faster. I hope this helps someone...

How to convert a SVN repository to GIT in Linux

Development, Linux
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Today we want to convert a SVN repository to a GIT repository. I did the same conversion at edorasware too. What you need is direct access (SSH access to the server where the SVN repository lies) to the SVN repository which you want to convert and have GIT installed on that server. If you do this on a production SVN repository you need to tell all developers to stop committing while you are doing the conversion to prevent an inconsistent state of the GIT repository. Let's start by creating a dump of the SVN repository. (be sure you have enough disk space) Browse to the repository and execute the following command: Now we have a dump of the repository which you can copy into a temporary folder where the conversion takes place. Next we create an empty SVN repository and load the dump into this repository. Execute the following commands to do this: This process leaves the original SVN repository intact such that you can go back to SVN if something happens while converting. Next we need to download the svn2git tool which was used to convert the SVN repositories from the KDE project to GIT. Execute the following commands to clone the GIT repository: Now we need to install some dependencies in order to make the svn2git executable. Install the libsvn-dev dependency and qt4. In ubuntu you would execute the following commands: After the installation browse to the svn2git folder and execute the following commands to make the executable: After this process you have the svn-all-fast-export executable inside the...

How to install ownCloud 5 manually on Ubuntu 13.04 with Apache 2

Linux
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Today we want to install ownCloud such that we can host everything at home and it is under your control. You can check the features at https://owncloud.org Ok first step is to download the ownCloud distrubution to your server and extract it in your web directory. (Normally inside /var/www) You need to have an Apache HTTPD running. Now you need to install some php dependencies which are needed by ownCloud. To do this execute the following commands: Next you need to ensure that 'AllowOverride' is set to 'All' in the 'Directory /var/www' section of your virtual host file. This is usually in '/etc/apache2/sites-enabled/000-default'. Update 23.11.2013: If you have Apache version 2.4.3 or later (default in Ubuntu 13.10) installed you need to add the following to the /var/www section of your virtual hosts file (which now ends with the .conf extension): Next we need to enable some Apache 2 mods with the following commands: Now open the browser and connect to your server and add '/owncloud' to the URL. Follow the installation instructions and select a database. I use PostgreSQL but you can also use MySQL or SQLite (file based database). But for larger installations you should use PostgreSQL or MySQL. After the installation is finished, you can test your ownCloud instance. If you need more documentation or need support goto http://doc.owncloud.org Thats all on how to install ownCloud on your own...