What is a “ghost call” and how to avoid it

☎ Have you ever received a call, but no one answered from the other end? ❌ In today’s article, we explain why they occur and how to avoid these ghost calls. ✍ Keep reading!

According to Wikipedia: “A ghost call is a telephone call for which, when the called party answers, there is no one on the other end of the call.”

Well, first of all we must differentiate the different reasons why this can happen to us:


Why do they call me and no one answers?

We receive a call from a landline or mobile number, but when we pick it up, we don’t hear anyone: in this case, it is most likely a telemarketing campaign using a “predictive dialer”.

These types of campaigns are automated with systems that run more calls than there are operators available to answer them.

The advocates of this system, among which NOT is GESDITEL, think that this way the number of calls is raised, and the waiting time of the operators is minimized.

If the phone number calling us is national, this is the most frequent cause of the “ghost call” effect.

The solution is simple: GESDITEL customers can block the calling number from our online panel, or request it from the web or by phone.

Users of other operators can contact their customer services. In case we receive the call on a mobile line, we can also do it from our smartphone, blocking the number and reporting it as spam.


Why do I receive calls with strange characters?

IP phones are network elements, i.e. they communicate with the rest of the world via the Internet.

Sometimes, some IP phones, regardless of the operator that manages the phone line, receive calls with strange characters that do not comply with the regulations (numbers that do not have 9 digits, and that do not start with 6-7-8-9). These calls are repeated without any time pattern, day and night.

When we pick up, we hear nothing…. What is going on?

The explanation of what happened, and its solutions, are very simple. When our IP phone communicates with the outside (issues or receives a call), it does so through a port, port 5060.

According to various sources, including ABC, “Half of the world’s traffic is generated by “bots”.” Many of these “bots” scan network traffic looking for “movement” on port 5060.

Once they have detected movements on this port, they “attack” the IP address of our phone terminal, managing to send calls to our phone while trying to take over our credentials.

Getting hold of them would allow the attacker to make calls at the expense of the line’s owner.

GESDITEL customers are in luck. Our telephone services include these security settings, and, therefore, this will never have happened to you, and for the time being it will not happen to you either.


How to troubleshoot security issues on IP phones?

For customers of any other telephone operator who have this problem, we provide the following solutions:

  • Hide your IP traffic: By changing the port through which we manage IP traffic, we “fool” more than 90% of the existing bots, minimizing the chances of suffering attacks from the Internet.
  • Configure your telephone terminal to disable the IP calling feature. This feature allows the SIP phone to make and receive calls over IP address (without SIP account). Many telephone handsets have this option enabled by default. We must disable it.
  • Configure the phone terminal to accept only trusted servers. This option forces the phone to accept requests only from the trusted server.

The instructions for making these settings depend on the make and model of the handsets. To find out how to make these settings on your handset, search Google for “ghost call solution +handset model”.

For Yealink users, I leave you the following LINK:.

Applying these simple instructions will prevent these attacks that generate our “ghost calls”, as well as prevent future attacks.

It is advisable to contact your operator to establish limitations on telephone consumption, and review your call list for the next few days. Because it is possible that the attacker has obtained our credentials and can generate telephone consumption to our balance, or even commit scams and crimes with our phone number.

GESDITEL customers already have limitations configured in the daily consumption and other specific per user that allow us to control and eliminate this uncertainty in the hypothetical case of a computer attack.

We hope this article on ghost calls has helped you understand what they are and how to avoid a ghost call.

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Por: Nati CaballeroPublicado el: 20 de mayo de 2022