How to connect to PPTP server from linux

How you could connect to PPTP server from linux to access your office network?

  • Goto Edit Connections -> Add New Connection

  • Choose Point-to-Point Tunneling Protocol (PPTP) as connection type

  • Provide the information you have received from your company administration team( e.g Gateway, User name, Password, NT Domain(Optional)) and save it

  • New connection with connection name will be available to dial under the connection manager -> VPN Connections -> Office VPN Connection(in our case)

How To Secure Apache with Let's Encrypt on Ubuntu

This post will show you how to set up a TLS/SSL certificate from Let’s Encrypt on an Ubuntu server running Apache as a web server.

Introduction about SSL

SSL stands for Secure Socket Layer. SSL is a protocol used for sending confidential data over the Internet. SSL creates a secure connection between a web browser and the server. In this process, SSL uses encryption to keep the data private.

Advantages of SSL

• Encrypts Information. SSL certificate ensures the data you send online are read by only the intended recipient and none else.
• SSL makes some changes in the original data so that the data can’t be read by the third parties.
• Having SSL certificate ensures authentication.
• Secure against phishing attacks.
• Better search engine rankings.

Install SSL certificate using Let’s Encrypt


• Ubuntu server with a non-root sudo user.
• The Apache web server installed and domain name properly configured.
• Your domain mapped with server IP.

Step 1 — Install the Let’s Encrypt Client

The first step to Let’s Encrypt SSL certificate is to install the certbot software on your server.

sudo add-apt-repository ppa:certbot/certbot

You will need to press ENTER to accept. Then update the package list using following command

sudo apt-get update

Install Certbot SSL using following command.

sudo apt-get install python-certbot-apache

Step 2 — Set Up the SSL Certificate

Following command is automatically install a new SSL certificate on apache server that is valid for only 3 months. A single certificate that is valid for multiple domains or subdomains. Execute following command.

sudo certbot --apache -d

If you can execute above command then it will ask some basic information like email, agree terms & service and enabling both http and https access. After install certificate, automatically changed apache configuration file as required.
When the installation is finished, you should be able to find the generated certificate files at /etc/letsencrypt/live.

Step 3 — Auto Renewal SSL Certificate

Let’s Encrypt’s certificates is valid for 3 months. Following command is to check for expiring certificates and renew them automatically.

sudo crontab -e

After execute above command, Your text editor will open the default crontab which is a text file with some help text in it.
Paste in the following line at the end of the file, then save and close it:

15 3 * * * /usr/bin/certbot renew --quiet

Now your domain is ready with SSL Certificate.

Installing Zimbra community 8.7 on Ubuntu 16.04


Zimbra email collaboration is the leading open source enterprise email solution and the most preferred alternative to Microsoft Exchange. It is now available in hosted, cloud and on-premise versions. Zimbra provides an excellent browser-based interface that allows users to integrate with mail clients easily. Silent Infotech provides consultation, implementation and migration services with support for your Zimbra email/collaboration solution.

Download zimbra based on your platform, from latest release Zimbra Open Source. Here we will choose Ubuntu 16.04 LTS 64-bit release and download it with wget. Get the download address location and download form machine where you want to install zimbra

Download zimbra

root@silent:/cd /home/
root@silent:/home# wget

Extract downloaded zimbra

root@silent:/home# tar tar xzf zcs-8.7.7_GA_1787.UBUNTU16_64.20170410133400.tgz

Prerequisite to install zimbra

Step 1 : In case the system configured by using DHCP, you need set an static IP for Zimbra Collaboration.

root@zimbra8:~# vim /etc/network/interfaces


If you have dhcp line:

allow-hotplug eth0 
iface eth0 inet dhcp


Then change it to static Ethernet configuration:

allow-hotplug eth0 
iface eth0 inet static
address 10.X.X.X 
gateway 10.X.X.X


Note, address : Zimbra machine ip,

gateway : router IP address in your Environment.

DNS Server, type your own Zimbra server if you will use an internal DNS server on Zimbra Server, or other IP in case you have a valid DNS Server already exist.

Step 2 : Set hostname

root@silent:/home# vi /etc/hosts       localhost mail

Step 3 : Reboot machine

root@silent:/home# reboot

Install zimbra

root@silent:/home# cd zcs-8.7.7_GA_1787.UBUNTU16_64.20170410133400/

root@silent:/home/zcs-8.7.7_GA_1787.UBUNTU16_64.20170410133400# ./

Now follow given steps to complete the installation:

Step 1 : Read and accept license agreement:

License Terms for the Zimbra Collaboration Suite:
Do you agree with the terms of the software license agreement? [N] y

Step 2 : Now it will check if some zimbra packages already exist

Operations logged to /tmp/install.log.zlP8ruf3
Checking for existing installation...
    zimbra-ldap...NOT FOUND
    zimbra-logger...NOT FOUND
    zimbra-mta...NOT FOUND
    zimbra-dnscache...NOT FOUND
    zimbra-snmp...NOT FOUND
    zimbra-store...NOT FOUND
    zimbra-apache...NOT FOUND
    zimbra-spell...NOT FOUND
    zimbra-convertd...NOT FOUND
    zimbra-memcached...NOT FOUND
    zimbra-proxy...NOT FOUND
    zimbra-archiving...NOT FOUND
    zimbra-core...NOT FOUND
License Terms for the Zimbra Collaboration Suite:
Do you agree with the terms of the software license agreement? [N] y

Step 3 : Select the services to be installed on this server.

To install Zimbra Collaboration on a single server, enter Y for the ldap, logger, mta, snmp, store, and spell packages.The installer verifies that there is enough room to install Zimbra Collaboration. If there is not, the installation stops.

Checking for installable packages
Found zimbra-core
Found zimbra-ldap
Found zimbra-logger
Found zimbra-mta
Found zimbra-dnscache
Found zimbra-snmp
Found zimbra-store
Found zimbra-apache
Found zimbra-spell
Found zimbra-memcached
Found zimbra-proxy

Use Zimbra's package repository [Y]

Select the packages to install

Install zimbra-ldap [Y] y

Install zimbra-logger [Y] y

Install zimbra-mta [Y] y

Install zimbra-dnscache [Y] y

Install zimbra-snmp [Y] y

Install zimbra-store [Y] y



Checking required space for zimbra-core

Checking space for zimbra-store

Checking required packages for zimbra-store

zimbra-store package check complete.











The system will be modified.

Continue? [N] y

Removing /opt/zimbra
Removing zimbra crontab entry...done.
Cleaning up zimbra init scripts...done.
Cleaning up /etc/security/limits.conf...done.

Finished removing Zimbra Collaboration Server.
Installing packages
Local packages  zimbra-core zimbra-ldap zimbra-logger zimbra-mta zimbra-snmp zimbra-store zimbra-apache zimbra-spell zimbra-proxy selected for installation
Monitor /tmp/install.log.sKlWbSLr for package installation progress
Remote package installation started
Installing zimbra-core-components  zimbra-ldap-components zimbra-mta-components zimbra-snmp-components zimbra-store-components zimbra-apache-components zimbra-spell-components zimbra-memcached zimbra-proxy-components....

Local package installation started
Installing  zimbra-core zimbra-ldap zimbra-logger zimbra-mta zimbra-snmp zimbra-store zimbra-apache zimbra-spell zimbra-proxy...done
Operations logged to /tmp/zmsetup.20160430-185719.log
Installing LDAP configuration database...done.
Setting defaults...

Step 4 : Update MX records

If it throws exception about a missing MX record as given below, which says your domain DNS records are not matching with zimbra server’s expectation, based on the hostname which is configured earlier. Find your /etc/hostname file and check DNS records to resolve the problem.


DNS ERROR resolving MX for
It is suggested that the domain name has an MX record configured in DNS
Change domain name? [Yes]

Create domain: []
MX: (

Interface: fd7a:4c04:5f10:0:20c:29ff:feb9:ecf8
Interface: ::1
Checking for port conflicts

Step 5 : Set admin password

Main menu
 1) Common Configuration:                                                  
 2) zimbra-ldap:                             Enabled                       
 3) zimbra-logger:                           Enabled                       
 4) zimbra-mta:                              Enabled                       
 5) zimbra-dnscache:                         Enabled     

 6) zimbra-snmp:                             Enabled                
 7) zimbra-store:                            Enabled                       
     +Create Admin User:                     yes                           
     +Admin user to create:     
 ******* +Admin Password                        UNSET                         

To change default admin password, select menu 7 and then inside zimbra store select 4, provide password and press enter

Type r to return to the Main menu.

Select from menu, or press ‘a’ to apply config (? – help) a

Save configuration data to a file? [Yes] : press enter

Save config in file: [/opt/zimbra/config.10687]:press enter

Notify Zimbra of your installation? [Yes]
Notifying Zimbra of installation via
Notification complete

Setting up zimbra crontab…done.
Moving /tmp/zmsetup.20160430-185719.log to /opt/zimbra/log
Configuration complete – press return to exit

Step 6 : Check installation

To check admin control panel:

To check user login:

Suggestions & inquiry are welcome

DMA Radius : How to repair "Incorrect key file for table ‘./conntrack/xxxx@xxxxxx@xxxxxx.MYI’"

Some times if your production server goes down due to power failure you might face below error while accessing “Connection Tracking Reports” in Radius manager.

Incorrect key file for table ‘./conntrack/2017@002d06@002d04.MYI’. try to repair it

Follow below mentioned steps to resolve issue.

How to repair table[Ubuntu]?

Go to database folder

cd /var/lib/mysql/conntrack
service mysql stop
myisamchk -r -v -f 2017\@002d06\@002d04.MYI
service mysql start

# don’t forgot to change table name

How to repair table[Centos]?

Go to database folder

cd /var/lib/mysql/conntrack
service mysqld stop
myisamchk -r -v -f 2017\@002d06\@002d04.MYI
service mysqld start

# don’t forgot to change table name


  • Use SSD or RAID based storage for faster IO and make sure you have plenty of disk space.
  • Use separate host for Connection Tracking database for better performance
  • Follow mysql performance tuning guide line

Zimbra Email Collaboration Solution Fits in all Businesses

Zimbra Email Collaboration Solution Fits in all Businesses

Zimbra email collaboration has more than 400 million trusted users worldwide. It is the leading open source enterprise email solution and the most preferred alternative to Microsoft Exchange. It is now available in hosted, cloud and on-premise versions. Zimbra provides an excellent browser-based interface that allows users to integrate with mail clients easily.

Zimbra UI

Silent Infotech provides consultation, implementation and migration services with support for your Zimbra email/collaboration solution.


  • Secure Communication for Businesses: Stayed connected with your business-class email in a secure environment with dedicated file sharing, tasks, and shared calendaring features. Zimbra collaboration solution ensures protected communication with higher security standards and transparency of an open source platform.
  • Excellent Collaboration Tools: Increase your productivity with a comprehensive set of collaboration tools and having complete control over company’s privacy and security.
  • Easy Collaboration from Any Device, Any Location: Zimbra enterprise email solution offers ease of access from anywhere, across multiple devices including smartphones and tablets, and both online as well as offline.
  • Open Source Offers Extended Collaboration: Extend collaboration further than an email with Zimlets and APIs to connect to other applications like Salesforce. Increase security through third-party integration with Zimbra Collaboration’s open framework.
  • No Downtime: Maximize benefits of carrier-grade collaboration with Zimbra collaboration solutions. It is the only platform with plenty of choices for larger telecommunications companies and ISPs worldwide. Performance and speed guaranteed.
  • Deployment Flexibility: Deploy Zimbra enterprise email solution through any of our trusted service providers or on-premise.
  • Save on TCO: With Zimbra, you can save at least 50% than Microsoft Office 365 and Exchange. Save on hardware, operations, and licensing. Get best savings on cloud based and on-premise Zimbra collaboration.

Why is Silent Infotech the Best Choice for Zimbra Email Solution?

  • Professional Zimbra mail consulting services
  • High-level architecture and design with low-level workflow details for easy deployment
  • 24×7 Zimbra mail server support by experts
  • End-to-end security with SSL and Firewall
  • Regular offsite backup of Zimbra for unforeseen disaster recovery
  • Experienced migration from one platform to another

Join us to know more.

Steps to Install Windows 10 on existing Ubuntu 16.04

Installing Ubuntu after Windows is easy and strait forward process. But to install Windows after Ubuntu is a bit tricky and not recommended. But you still have to do it sometimes.

So, here are the steps to install Windows 10 when you have Ubuntu 16.04 already installed. And you want to run both together.

1. Prepare partition for Windows Installation in Ubuntu 16.04

  •  To install Windows 10, it is mandatory to have Primary NTFS partition created on Ubuntu for Windows.
  • Create Primary NTFS partition for Windows installation using gParted OR Disk Utility command line tools. If you have existing logical/extended partitions in which you want to install windows, then you need to delete that partition and create new Primary Partition. (NOTE: All data in the existing logical/extended partition will be erased. Because you want Windows there.)

2. Install Windows 10

  • Start Windows Installation from bootable DVD/USB stick.
  • Once you provide Windows Activation Key, Choose “Custom Installation“.
  • Select the NTFS Primary Partition(we have just created in Ubuntu 16.04)
  • After successful installation the Windows bootloader replaces the grub. So, when Windows boots, you won’t see the grub menu to choose Ubuntu. So, Next you need to install grub again for Ubuntu.

3. Install Grub for Ubuntu

  • To install and fix grub, you need LiveCD or LiveUSB of Ubuntu.
  • Once you load Live Ubuntu, Open Terminal and fire following commands to install boot-repair and let it fix the Grub.
    sudo add-apt-repository ppa:yannubuntu/boot-repair && sudo apt-get update
    sudo apt-get install -y boot-repair && boot-repair
  • After installation, boot-repair will get automatically launched.
  • Make sure to select “recommended repair” option to repair grub. Reboot.
  • You will now have a Grub menu on boot, where you can choose from Ubuntu, memtest, and Windows 10

Odoo – Payfort Payment


PayFort is the Most Trusted Online Payment Gateway in the Middle East because of the local currency support and local technical support. They have clients from various industries and who are industry leaders in Middle East like and Carrefour UAE.

Silent Infotech provides highly integrated  Payfort payment gateway module leveraging Odoo’s architectural modularity. This type of integration allows the Merchant’s Customer to check-out on the Merchant’s payment page without being redirected to external sites and thus enjoy the seamless User experience.

For more info & enquiry contact us @

Door Eye – Home Security Device


Introducing Door Eye

Door eye is smartly designed home security appliance which acts upon the door bell ring provides the owner with the real-time photo capture of the person ringing the door bell.

  • The module is simple and easy to install.
  • It works with the existing doorbell wiring of the Home.
  • Can be mounted at required angle and height.

How it works

It works as simple as when someone rings your doorbell, your smart-phone blurts and buzzes, and with a tap, you can view the captured snap of the visitor. It doesn’t matter if you’re in the kitchen, at the office.

Key functions

  • Visitor Ring alert – System alerts with the visitor’s image when anyone rings the doorbell.
  • Motion detected Alert – It alerts user detecting visitor with its Motion detection Sensor.
  • User demanded capture – User can request capture of the door front anytime/anywhere from the Application.
  • On Demand Video stream – the real-time video stream of the visitor is no more away than a single tap on the app.


  • It is your private and trusted gate keeper to protect your home.
  • Images being transferred to the phone will be encrypted.
  • User can stop notifications upon losing phone.
  • Add/Remove family members right from your app securely.

Odoo Cluster Setup on Rancher

At Silent Infotech we have successfully deployed odoo cluster using rancher platform in order to mange the huge number of users and good amount of concurrent user load.

What is Rancher?

Rancher is designed to solve all of the critical challenges necessary to run all of your applications in containers. Rancher provides a full set of infrastructure services for containers, including networking, storage services, host management, load balancing and more. All of these services work across any infrastructure, and make it simple to reliably deploy and manage applications.

What is docker?

Docker containers wrap up a piece of software in a complete File System that contains everything it needs to run: code, runtime, system tools, system libraries – anything you can install on a server. This guarantees that it will always run the same, regardless of the environment it is running in.

Odoo cluster setup

Odoo Cluster Architecture

Odoo cluster has been setup using below set of containers/docker instances

  • 3 X Odoo Instances
  • 1 X DB Instance(Postgres)
  • 1 X Load Balancer



Zimbra Collaboration Suite

A secure and open unified collaboration solution.


  • Built on security standards and open integration with industry security products.
  • Zimbra is committed to transparency and rapid response to vulnerabilities.
  • Deploy Zimbra products on premises or in the cloud (public or private) to ensure your data is where you want it and under your control.


  • Mobile-enabled browsers or Zimbra mobile apps available anytime, anywhere.
  • Extend collaboration to mobile workers and customers of all sizes and geographies.
  • Promote collaboration and lower adoption barriers with mobility.


  • Easily fit Zimbra into your existing solutions and infrastructure and quickly add additional functionality via Open APIs.
  • Take advantage of extensions, integrations, and customizations developed by Zimbra, by its trusted partner network, or the open source community.


  • Zimbra software supports any size organization all over the world; from small enterprises, to governments to the most demanding service providers supporting thousands of companies and millions of users.
  • Whether on premises or in the cloud, Zimbra scales to fit your needs and budget.