Mobile Education

I decided to publish a video of the project I have been working with Dr. Pavlin Dulev for some time now. Please let me know if there is any interest corporate or not, we are seeking sponsorship. The server side consists of a panel for the teachers where they can set up tests for their students and share video lecture material. Everything is downloaded to the mobile device (Android) and from there the student can do the tests or view the lectures. For best results view the video in Full Screen Mode, high resolution. The teachers panel is coded in PHP+MySQL, the Android application is Java+Android SDK. 

Zentyal - Mail Server - Webmail and RDNS

I have set up a mail server based on Zentyal and was very happy with it, but noticed a issue with the RDNS test. So I remembered that I just clicked Next when I set up the server on host name - I should have thought on the consequences first. When you set up Zentyal and set the domain name and hostname be sure that it matches what you need for the mail service. If you change it afterwards in System>General> Hostname&Domain you will have to recreate all the mailboxes and aliases in Office>User and Computers>Manage. But this was only the begining of this adventure:

I got an error on the webmail:

DATABASE ERROR: CONNECTION FAILED!
 
Unable to connect to the database!
Please contact your server-administrator.

To fix this:
Disable the webmail service in 'Module Status'
sudo nano /etc/mysql/conf.d/zentyal.cnf
and change this line as shown: innodb=on
then: service mysql restart
get the MySQL pass: sudo cat /var/lib/zentyal/conf/zentyal-mysql.passwd
then: sudo mysql -p
Execute this query: DROP DATABASE roundcube;
Run this script: sudo /usr/share/zentyal-webmail/enable-module
Re-enable the webmail service in 'Module Status'

Easy huh. Everything is working now. Think about it when you click Next.

Mikrotik Setting up ntp client

Having logs and not having the correct time on them is as bad as not having any logs at all. This is how you can set up your ntp client to have the correct time on a Mikrotik.

/system ntp client> set enable=yes primary-ntp=[:resolve 0.bg.pool.ntp.org] mode=unicast

Don't forget to change the ntp server to whatever you need.

You can check the current time afterwards:

/system clock> print

VMware VCA Certification

VMware is offering now free training courses. During the holidays I got really bored so I took the VCA-Cloud Training course and did the exam today for breakfast and passed it - VMware Certified Associate - Cloud.

Try the free courses they are really useful for understanding the basic concepts, there is also free practice exam available on the site:
http://mylearn.vmware.com/mgrReg/plan.cfm?plan=40721&ui=www_edu

VMware OVF Tool

Tried converting a VMX file today to OVA so I can migrate it to another environment. It's pretty easy actually all you have to do is: 
1. In cmd go to C:\Program Files (x86)\VMware\VMware Player\OVFTool
2. Convert with ovftool by executing ovftool.exe <path>\<file>.vmx <path>\<file>.ova

Mikrotik Destination NAT

This is very useful in case you want to make services available from your router to the public. In the example I have shown destination NAT for FTP. Also don't forget to allow such traffic in the firewall - might get filtered out.

/ip firewall nat add chain=dstnat dst-address=<real ip> protocol=tcp dst-port=20-21 action=dst-nat to-addresses=<internal ip> to-port=20-21