Developers Club geek daily blog

VoIP + Cisco Packet Tracer

1 year, 3 months ago


Working with the Cisco Packet Tracer program, often noticed in it different telephone devices, and also software on client devices by means of which, it is possible to organize phone calls. In this regard, there was an idea to make a model of the network consisting of all devices of this simulator (cisco packet tracer 6.2) which can call and receive calls. When writing this article, there was a question: Whether "It is possible to be prepared for examination of CCNA Voice, by means of this program?". And on this question, I will try to answer in this article.

Read more »


The third New Year's kolltsentr: superrapid development on ReactJS and Typescript

1 year, 3 months ago
With coming, colleagues! We in voximplant have a tradition — before each new year we do New Year'skolltsentr on which we roll new features of our platform. This year by a feature it happened especially much. Except video calls and record of video, we began to use actively typescript and react. The modern "hipstersky" stack of technologies extremely accelerates a razrabota: from the moment as the maxim log suggested us to make kolltsentr with models as Snow Maidens and to the first accepted video call there passed less than two days. This year we did not begin to do the announcement most promo on Habré, after all a format not that, we want to communicate about a code and development, huh? Therefore under a cat I will share our experience of creation of a solution in a short time and I will tell what difficulties we faced.

Read more »


Cloudy call center in the cloudless region. Extraordinary New Year's adventures of ITooLabs on the Balkans

1 year, 3 months ago
Traditionally, before the Newest Year, it is accepted to write about results of the year leaving about plans for year forthcoming, to congratulate clients, partners and colleagues on holidays. We do not want to break the developed tradition and today we publish a post which for certain will create the necessary and correct mood at readers of the blog ITooLabs. We want to tell about how there is a cloudy business of our foreign partner, the Balkan telecom operator of VoxNet as work of the Balkan colleagues looks and as the ITooLabs platform helped to automate the big European call center working at the entering and outgoing calls. At our request the Macedonian colleagues made many photo and even wrote a New Year's video congratulation.


Read more »


Use of cloudy automatic telephone exchange of pbxes.com for expansion of opportunities VoiP/SIP of telephony

1 year, 4 months ago
So it developed that I have several SIP numbers from different VoiP of operators in the different countries of the world (the USA, Israel, Ukraine, Russia). At some point, having received the next call with the sentence "to purchase an elephant" on my Israeli number at 4 o'clock in the morning (I in the USA, and the Israeli telemarketing specialist, naturally, does not guess it), I understood that it is necessary to do something.

In a case with the Israeli provider everything was simply — in a personal account of provider changed settings, having redirected all calls from unfamiliar numbers (which not in "white list") to voice mail from 9 in the evening to 7 in the morning.

In total nothing, but through any time I began to receive calls with the sentence to purchase the Ukrainian elephant (on the Ukrainian numbers from Atlantis Telecom and Intertelecom) and the Russian elephant (on number from For nothing). And here it is already worse — in personal accounts of these three providers there is no opportunity to redirect a call to voice mail by the schedule or to block some number. In For nothing and Intertelecom there is no voicemail at all, with readdressing too not everything is good (in For nothing — only unconditional forwarding), in Atlantis Telekome and Intertelecom — readdressing only on telephone numbers, but not on SIP URI.

As a result, the solution with use of cloudy automatic telephone exchange of pbxes.com was found.

To whom it is interesting, the application under a cat (it is a lot of pictures)

Read more »


Responsibility of vendor. Who is responsible for accidents?

1 year, 4 months ago
Last Thursday our service endured the largest accident in the history. One of installations on M9 remained unavailable of an external network within several hours. What happened? What to do? How the responsible vendor has to arrive? How to save reputation of vendor of a telephone platform No. 1?

It is considered that in time the corrected error is not an error any more. That, we will check correctness of an aphorism in practice. Usually marketing specialists write the plan of publications for the month ahead and the ideology of each post is something like motivating "Quicker, above, is stronger". Also we not the exception is so accepted, but this time we will depart from marketing dogmas and we will fairly tell about the appeared problem without the rustling New Year's Eve PR wrappers.


Read more »


The market of Virtual automatic telephone exchanges died

1 year, 4 months ago
The market of Virtual automatic telephone exchanges died, without having managed to appear. MSP did not begin to use VATS, despite their availability. Attempt to expand the market on small business which has no funds for purchase of traditional automatic telephone exchanges was not repaid. At small and microbusiness there are no reasonable reasons to pay for VATS.

Read more »


As we taught 1C to generate the IVR menu for Asterisk

1 year, 4 months ago
The last years penetration of IP-telephony into business happens with great strides. Every day more and more opportunities appear. Employees can work not only at office, but also in general worldwide. To connect telephony to the employee several clicks, any wires and separate sockets are enough. The companies use record of talk, integration of telephony with CRM systems. Each company respecting itself connects multichannel number or even pays for each call of the client, using number 8 800.

To give to the client the cell phone becomes a bad form, the address of the client has to be registered in CRM and is guaranteed processed. To each employee the internal extension number, and most often is assigned, knowing extension number, it is possible to contact the necessary employee quickly. The automatic telephone exchange knows where now there is an employee, and will be able to connect the client with the necessary IP phone at office either the mobile phone, or even the SIP softphone installed on the notebook or the smartphone.

But progress has also other party. Multichannel number becomes similar to a firewall. It protects employees in the company from calls of clients. On the way of the client the IVR menu, or even the multi-level IVR menu appears, and only you do not say that my call is very important for you :)

Read more »


We test quality of passing of VoIP across the general canals (Windows)

1 year, 4 months ago
Earlier we in details sorted utilities for Android and iOS for testing of link quality from the device to IP-ATC. There was only Windows.


Read more »


Critically dangerous vulnerabilities in popular 3G-and 4G-modems or how to construct the Big Brother

1 year, 4 months ago


The report is logical continuation of the research "#root via SMS" completed in 2014 by the SCADA Strangelove command. Research affected vulnerabilities of modems only partially, within wider description of vulnerabilities of the equipment of telecom operators. The description of all found and used vulnerabilities in 8 popular models 3G-and 4G-modems available in Russia and worldwide is hereunder submitted. The found vulnerabilities allow to carry out remote execution of a code in web scenarios (RCE), any modification of a firmware, mezhsaytovy counterfeit of requests (CSRF) and mezhsaytovy execution of scenarios (XSS).

In research the most complete set of vectors of attacks to the clients of a telecom using these modems is also described — it can be identification of devices, code injection, infection of the user computer to which the modem, counterfeit of the SIM card and interception of data, position fix of the subscriber and access to its personal account on the operator's portal, and also target attacks (APT) is connected. Slides of the presentation of this research with ZeroNights 2015 are provided here.

Read more »


Asterisk + LUA: fast start

1 year, 4 months ago
For the last year on Habré there were several articles about use of a dialplan of lua in asterisk (time, two, three, four). It is rather interesting method of writing of flexible and powerful dialplan. But to try such method of writing of dialplan it is necessary to spend time quantity: to set the necessary libraries, to rebuild with necessary for options an asterisk.

In addition many users have asterisk'the different level of preparation: someone is closer to system administration or even to traditional telephony, than to programming. Plus specifics of telephony — are better not to load with unfamiliar experiments the working systems once again, and to carry out tests and experiments on the notebook — it is necessary to litter system. Generally, there are many reasons "to postpone for later".

I want to show in this article to everyone and working with an asterisk as, using docker, it is possible to feel taste of the flexible scenarios lua quickly. And then to these it is worth deciding to use further in practice or not. (To whom it is uninteresting to read, and it is interesting to watch and listen — at the end of the text to 6-minute video with highlights and result.)


Read more »