Download ESXi 6.0 patched with Realtek 8168, 8169 and DLink DGE-528T NIC

Relief for all those Virtualiztion Enthusiast who wants to build their Virtualization lab in their home with simple hardwares. Unfortunately, ESXi 6 donot support NICs made for consumer purpose and only supports server grade NICs. But why buy those costly NICs when all motherboards now-a-days provides us with gigabit NIC and even if you don’t have an on board gigE NIC, DLink provides a nice DGE-528T GiGE NIC for our use.

Now, for those who are new with ESXi 6 and stuffs, I have created an ISO with latest ESXi 6 which is patched with Realtek 8168, Realtek 8169 & DLink DGE-528T Drivers. Just install the ISO using your pen drive or a CD and all your supported NICs will be detected automatically.

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Installing playSMS with Gammu in Ubuntu Server 15.04 – Part 3 – Gammu installation, configuration & verification

Okay, so you have been through some comparatively easy steps but now is the ultimate step leading you to the final configuration of your server using Gammu gateway. So, have patience and configure it step by step..

For this demonstration, I will be using ZTE MF 190 dongle with a SIM Card.



Also I would like to say that since I am working in a virtualized environment there are some passthrough options required. Though I will go through those steps, you can ignore if you don’t use ESXi. Unfortunately my hardware did not support Passthrough option directly (Direct I/O) so I had to mount my USB of another PC to my server.
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Installing playSMS with Gammu in Ubuntu Server 15.04 – Part 2 – playSMS installation & configuration [with Video]

Hope you have successfully followed my first part of this tutorial series and implemented basic requirements for installing playSMS now.

Procedure for installing playSMS in Ubuntu Server 15.04:

  1. Go to Check out the latest version available, like 1.3.1 for now. Click on it. Right click on playsms-1.3.1.tar.gz –> Copy link address.
  2. Open Ubuntu shell. Download the playSMS archive using the following command:
  3. Continue reading…

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Installing playSMS with Gammu in Ubuntu Server 15.04 – Part 1 – Preparing the server [with Video]

Hello everyone, in this tutorial we are going to see how to set up your own SMS Gateway using playSMS & Gammu. I am writing this post after getting inspired from Mr. Syed Jahanzaib blog. Also, I must thank Mr. Anton Raharja for creating such a wonderful easy-to-use application – playSMS.

My main intention in writing this blog post is to make people aware of this useful application and help them setup their own sms gateway conveniently. I have mostly followed instructions from playSMS original documentation though there are some modifications to suit my needs. Let’s begin…

What is playSMS?

playSMS is a free, opensource web based SMS Management platform having several features like sending/receiving sms, sms poll, sms quiz and much more. [Find more about it here]

What is Gammu?

Gammu is also a free, open source command line utility, which you can use to control your phone. It can be used for SMS retrieval, backup, phonebook access and much more. It can communicate directly with mobile devices including phones and dongles. [Find more about it here]

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How to configure IOU in GNS3 for real Cisco Switching Labs

Use .ova for GNS3-IOU instead of pre configured VM.

We all may have heard the saying GNS3 is great for practicing routing labs but switching Nah Nah!! Don’t underestimate the power of GNS3. It has a special IOU feature which will let you emulate real Cisco Switch both L2 & L3 in GNS3 without any trouble.

If you want to know what is an IOU? Refer to this excellent article here else follow along…

To configure IOU in GNS3 you will need the following files:

  • GNS3 (I used v1.2.3)
  • Virtual Box
  • GNS3 IOU VM (or .ova file available on GNS3 Official Site)
  • L2 IOU image
  • L3 IOU image
  • License file

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How to give ICMP high priority in Mikrotik Router?

Hello again.. Many of my friends using mikrotik devices in their network complains that whenever users starts downloading anything ping to their gateway (Mikrotik NAS) becomes unexceptionally high and gradually results in “Request timed out”.

After inspection I found that whenever users uses 100% of their allotted bandwidth, since we have not assigned any QOS(Quality of Service) for ping (ICMP Protocol) the request drops.

For this we need to create some mangle rules for marking connection and packet for ICMP requests and ICMP reply separately and then assign a simple queue mentioning the packet mark assigning a fixed bandwidth (say 512 kbps) for it. Then we can see even if users download at full bandwidth, the ping will be <1 ms to 2 ms max.

But unfortunately, hotspot users still faces a problem as when they log in the ICMP queue is moved below and thus reduces its priority. There is also a simple solution to it as we can simply add a script in user profile which will move the ICMP queue to the top(position 0) each time an user logs in.

Thanks a lot to Mr. Syed Jahanzaib for his valuable inputs.


  1. From IP -> Firewall -> Mangle Create a rule for Chain Prerouting, protocol ICMP. (For ICMP Requests)


  2. In Action we will mark the connection and give a name – icmp-con.

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How to protect your mikrotik router from DDoS Attacks – Basics

Distributed Denial of Service Attacks or DDoS is quite popular these days and it’s not hard to guess the the name of the originating country – China/Hong Kong tops the list of the attackers. Huh!

It has been a long time I’m working with mikrotik devices. So, it is not anything new for me. Guess what I faced DDoS first time in my home network. Trust me, it took my whole network down in minutes. So, just imagine what would happen to an enterprise network! Anyways, if you need to know more about it just google it and you will find a whole lot of article on it.

So, whenever you are configuring your mikrotik router for the first time it’s better if you configure the filter rules to prevent the attacks – “Prevention is better than cure!”

General Symptoms:

  • Full WAN uplink bandwidth utilisation even if no clients are connected to your router.
  • Extremely high  latency.
  • Several unknown IPs connected to your router’s public IP. [See this from the torch option and sort by Rx/Tx]
  • If you are curious enough and do some IP lookups you can see those IPs are of mainly CHINANET network. Beware!!

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Gaining access to an unconfigured Cisco 3750 Switch without Console, Telnet and SSH Access

Huh!! What happens when you need to configure a Cisco 3750 immediately for production network but unfortunately you don’t have console, telnet, or SSH access? I know it’s damn scary and if it happens at 02:00 hours then you have no one to help you.


Recently during an installation, I faced the exact same situation where I was presented with a Cisco 3750 switch but no methods of accessing it. Forget about SSH and Telnet as no Management VLAN was configured in it [It was totally an unconfigured one].

You might be thinking of Console access. Right? Damn it was not accessible too. Let me tell you the problems in brief.

  • Only 1 PC had a Serial port and had only Ethernet to Console cable. No USB to Serial Converter were there.
  • Console only displayed debug messages but keystrokes were were accepted.
  • All the settings on my hyper terminal were correct and it was as per Cisco’s recommendation.
  • Tried variations of Flow Control, baud rate etc but none helped.
  • Tried atleast 4 different applications for console access including putty, hyper terminal, secure crt, tera term. Results were all same.
  • Tried 4 brand new console cables.

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Monitoring & Securing your Cisco devices with Syslog & TACACS + Server – Basics

While deploying logging and authentication solution for a company, I came across a very interesting technology called TACACS + and Syslog. Though I have worked with Syslog previously but TACACS was a new protocol for me. Now, why suddenly someone would deploy these two protocols and also at the same time? Yes… you guessed it right – SECURITY was the main reason behind the deployment of these two.

First of all TACACS is an Authentication, Authorization and Accounting (AAA) server used for centralised authentication of users for device management unlike RADIUS servers used mainly for user authentication for wire and wireless network access.

Coming to the syslog portion, I can definitely say that all network admins must implement syslog server for better monitoring of their devices and take immediate action on any emergency incident. You won’t believe what I found after I enabled syslog for one of our cisco switch – NUMEROUS BRUTE-FORCE ATTACKS !!! Those attacks generated mainly from China and Hong Kong based IP Address. We all know that there are 7 types of facility. A facility is used to specify what type of program is logging the message. This lets the configuration file specify that messages from different facilities will be handled differently. The list of facilities available are:

Value Severity Keyword Description / Examples
0 Emergency emerg Multiple apps/servers/sites. This level should not be used by applications.
1 Alert alert Should be corrected immediately, An example might be the loss of the primary ISP connection.
2 Critical crit May be used to indicate a failure in the system’s primary application.
3 Error err An application has exceeded it file storage limit and attempts to write are failing.
4 Warning warning May indicate that an error will occur if action is not taken, For example a non-root file system has only 2GB remaining .
5 Notice notice Events that are unusual but not error conditions .
6 Informational info Normal operational messages -no action required. Example an application has started, paused or ended successfully.
7 Debugging debug Info useful to developers for debugging the application.

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How to install Radius Manager 4 in CentOS 7 [with Video]

A little Introduction…

Again I’m am writing about radius manager after a long time. But this time something more updated that is installation of Radius Manager in CentOS 7 which is currently the latest Cent OS version available. Here I will do the installation in a 64 bit version of CentOS 7 downloaded recently from CentOS Official website.

As we all know Radius Manager is a product of DMA Softlabs. Their support team told me that CentOS 7 is not compatible and told me to install 32 bit version of CentOS 6. But I thought of installing the latest OS ofr more updated and secured feature sets.

Initially I faced a lot of problem while trying to install Radius Manager 4 in CentOS 7. But eventually after lot of research and discussions with Mr. Syed Jahanzaib helped me to come up with a solution and install Radius Manager 4 in CentOS 7 perfectly.

However, If you want to install it in Ubuntu Server follow this.

Initial Prerequisites:

  • CentOS 7 (64 bit preferred)  – Downloadable from CentOS Official website – CentOS-7.0-1406-x86_64-DVD.iso
  • Radius Manager 4.1.6 – Downloadable from customer portal of DMA Softlab.
  • Radius Manager License Files – lic.txt and mod.txt – Downloadable from customer portal of DMA Softlab after purchase or trial.

Note: If you need to change MAC for CentOS 7 please refer to my tutorial here.

Update: Some users are facing yum repo issues after installing epel. To solve that:

1. nano /etc/yum.repos.d/epel.repo

2. Replace https with http.

3. Save and exit.

4. yum repolist. Verify installation is successful.

4. Issue yum update

 Steps to install Radius Manager 4 in CentOS 7

  1. After you clean install CentOS 7 with proper NIC MAC Address configured, install nano for editing the configuration files.
    yum install update
    yum install nano
  2. Disable SELinux by editing the following and changing SELINUX=disabled
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