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Nubis Novem

IT consulting company with real cloud experience

Category: architecture

Self Control: Windows server connected by VPN service to itself

There were times when we were looking for simple yet unorthodox solutions; and this case was one of them. Imagine, if there was a Windows 2012 server with its standard VPN service (RAS, or, Remote Access, actually), configured and operational. The only problem was that static IP of the server (as seen by a connected user) was not up at all times. For instance, assume DHCP IP range for VPN clients was 172.0.2.1 – 172.0.2.199. That makes first address of the range, 172.0.2.1 the server’s address that is accessible by VPN clients (inside VPN tunnel). When server just started that IP would be down – not even pingable, let alone not routable. The IP address becomes live as soon as first VPN client is connected from outside to the RAS service. That presented a challenge for application jobs configured to run in both modes: locally on the server and from remote locations connected to the server. We would configure 172.0.2.1 as a universal connection point for all the applications and grant proper server firewall exclusions, though… they would not be able to connect if no external users connected to the VPN service yet.

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Amazon AWS EC2 instance automatic shutdown by idle CPU

Amazon AWS instance may become very expensive when running 24/7. Our solution? An automatic shutdown when there is no need to have that server online. This recipe is simple when implemented with AWS’s functionality added not so long ago which was called CloudWatch monitoring.

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Printing via parallel port LPT interface on virtual Windows XP under Hyper-V

The main benefit of Windows XP mode on Windows 7 (virtual Windows XP instance under Hyper-V) would be to run legacy DOS applications or other older software that may not be compatible with newer versions of Windows. Also, some of those beasts would not know any better than to print directly to a hardware parallel printer port or LPT. For example, one of that legacy software is FoxPro. The LPT requirement presents a clear challenge since Microsoft did not provide an interface or driver for virtual Windows XP instance to access the host’s printer ports.

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Debian Jessie from Discovery to Mastery

A new edition of The Debian Administrator’s Handbook by Raphaël Hertzog, Roland Mas—the third one counting only English editions, and the seventh if the first four French-only are included—has been issued by Freexian. Shortly after the first English edition, communal experience with the book has justified the the in its title, the book becoming both the most widely read introduction into Debian and the most used single handbook, leaving out the documentation itself, of course.

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Server Name Change Surgery

Say, you have a stand-alone Windows 2008 R2 server that is not part of a domain. You decide that it would make more sense to adjust the server name in the system properties (Computer name – Change) from WinServ1 to a more meaningful WinDevelServ1. After mandatory server reboot you discover that (surprise!) Remote Desktop licensing is not active anymore. A brief error message on dashboard icon makes it clear that you have 120 days to activate the license or else users will lose their ability to connect via Remote Desktop.

What went wrong is one of the gotchas of Windows networking. Server name needs adjustments in various places of the system during name change and the Remote Desktop license server setting is apparently one that they forgot to take care of.

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Mirrored to oblivion

We have made a trip to data center recently to replace a faulty 900Gb hard drive in a RAID-10 logical volume of a 3.5 year old HP server. In the modern age of cloud hosting we still manage a few physical servers, for various reasons but mostly for our clients. Since last year we knew the drive may fail due to growing number of soft errors and ordered two extra drives in advance to be ready for day X: one as a replacement and another as a spare for that volume.

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Friendly interface considered harmful

“Friendly interface” has become a term universally accepted. Nobody seems to ponder on the message of those words. But pondering over the phrase gives you the shivers: the programs though creatures of our mind seem close to conquering the world while definitely breaking loose of our control.

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