To your kind attention!


A few words about myself and have been in the IT world more then 15 years working and freelancing, now I own a small IT company (GEMA SOLUTIONS) for telecom and software projects.

I started with the main idea to gather, log and show howto do stuff, solve problems and save you time and energy reading through hard understandable blogs,post, wikis and so on.

I will post very specific problems and solutions to them, with simple as possible guide.

Mikrotik Automated Backup

I want to share a neat way how to automate the backup of your Mikrotik configuration.The script provided here i use to do FTP backups 3 times a day.

I have a couple of these devices and i change the configuration pretty often on them, so i had to automate the process. While searching the web I have found this cool blog containing Mikrotik Automated Backup script.

Thanks for the nice script Harry B!

With some small modifications this script works perfectly doing two files export and backup of the whole configuration: Continue reading

Mikrotik DDoS and SYN Flood

Mikrotik DDoS and SYN Flood rules

I will present you some rules which you can apply to protect yourself from some of the DDoS or SYN Flood attacks or at least to mitigate as much as you can.I say some because it depends how much traffic Your ISP->Your Connection(s)->Your Devices can handle.I consider this attack very dangerous as you can do very little or nothing in some cases if you experience traffic of lets say around 100Gbit/s.Very little organizations can handle this kind of traffic.It depends how much enemies you have made and how much botnet zombies they hired from the attracker/s for the attack.

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Configure BIND for Active Directory

Configure BIND for Active Directory, BIND9 and newer versions support integration with Active Directory Controllers.If you already have running Primary and Secondary BIND servers in your network and want to integrate it with Active Directory Controller this is what you need to do.Let’s say your domain controller is in ( i would suggest you do a subdomain for you Active Directory like “ad” under your main domain “”) and your domain controller name is DC1:

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ZoneMinder and low CPU usage

I use ZoneMinder for various reasons, but mostly because it’s free and from my point of view the only free open source system for video surveillance which is worth your time and money if you donate.

I would like to share with you my experience.How I got a significant low CPU usage from a third party JPEG library, which I use on my CentOS 5 installation with ZoneMinder.This library is well written to optimize the JPEG processing power of the CPU.

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Elastix on OpenVZ

Elastix on OpenVZ installation.

Just recently I had to install Elastix on OpenVZ. This post on the Elastix forum will help you to install DAHDI. The idea is very simple, as every complex problem has simple and elegant solution, and I can confirm you that from my years of experience. I will give two words Physical to Virtual, and I hope this ring some bells :), here is what you have to do.

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Split-horizon DNS

Also known as split-view DNS, split DNS or DNS multi-view.

The Main Objective of Split-horizon DNS:

To use different EXTERNAL and INTERNAL files to differ request originating from Internet and local net.Make sure you use BIND9 or newer to support Split-horizon DNS.

Split-horizon DNS

Split-horizon DNS

The key moment in Split-horizon DNS:

As you can see on the setup above the external xfer is done by a different IP address on the secondary DNS server which allows Primary DNS server to differ the INTERNAL and EXTERNAL files.So to the basic you have to have two DNS files on the primary DNS server and let’s say you named them external.mydomain and internal.mydomain.The external.mydomain will contain only external IP addresses and internal.mydomain will contain only internal IP addresses.

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