Building a VPN for Mobile Devices at the Network Level

It is of no surprise that still VPNs (Virtual Private Network) are treated as pariah and people have a reservation from this technology. In this article I will elaborate how convenient, simple and secure this security technology is and how you can set it up on your smartphone without configuring complex software settings or buying a hefty subscription.

Let’s Clear the Air

Let’s begin with a question and end up answering confusions why VPN? This technology is used to stay anonymous and isolated via tunnel and enables data transfer between two devices through one of many intermediate nodes.

Mobile carriers can be used to build a VPN by utilizing multiple network protocols like;

• IPSec

• L2TP


These can be complemented with different third-party software products like OpenVPN, Cisco, and AnyConnect. But before you startup building a mobile VPN yourself I would like to clear the air, such requirements need come up with specific restrictions, and neither I nor anyone can help out in those circumstances. The problems are as follows;

The device you are willing to commemorate as a VPN should be compatible with the above-mentioned protocols at software and hardware levels. This problem is cured by installing a third-party application which is easily available on the internet.

One more restriction is to fine-tune and customize technology. This issue occurs on both smartphones and laptops no matter how modern the device. Although, it is relatively easy to work with the latest tech than with an old one. Furthermore, the old devices might end you up with new issues.

Smart organizations tend to work with reliable and leading VPN provider in the market. They want to keep their data secure and cybersecurity air-tight. Which as compared to end users is as irrational as people often disable or forget to enable VPN which can get the company overboard.

You can evade from such problems especially when you use a VPN at the network level. In particular case of mobile phones, a VPN for mobile can be implemented to any device that is capable of transmitting signals with the right network and correct protocols. It does not matter which settings are configured on the network; if the data passes under the right protocols, it will always be protected. The device gets its IP address which is already configured in it. The VPN network remains isolated as only the devices within the network can exploit it.

How does it Work?

To understand how it works we have to focus on the basics. Mobile VPNs work on the principles of telecosto and the B2B segments. The data network is connected via GPRS, HSPA, LTE, and others. There is no common platform that these network administrators use like VLAN, Routers or Switches. Instead, they rely on Packet Core (PS Core) and Radio Access Network (RAN).

Generally, every smartphone device has a sim card registered in the network. Before transferring data packets, one must switch on the transfer session which is often referred to as (PDP context) on the gateway GPRS Support Node (GGSN).

When initiating a session, there is a parameter where you are supposed to set up known as USB modems. This further asks for these three domains;


• Login

• Password

APN (Access Point Name) is an important entity that influences the logic of GGSN. GGSN acts differently every time a session is initiated. A DNS and IP Address is awarded to the device as a by-product of successful processing of the user’s request and also ends up activating the data transfer session.

Take notes of the following important features;

• While initiating a session request, make sure the smartphone does not receive the exact same IP address.

• It totally depends on the mobile operators to reduce the network parameters, so keep note while changing the APN field on both SGSN and GGSN.

A basic question here is;

What type of IP address is awarded to the subscriber? The IP is determined by the configuration of the APN which requests to activate the session. Around 99% of data transfer takes place using regular internet access.

Is this the only Solution?

No, considering the above information, there can be several ways to build a mobile VPN. They all will differ with one another with the combination of the following features;

• Both dynamic and static IPs can be assigned; this is determined by APN and Radius Settings.

• IP Addresses can be issued using Radius Server which can be configured under the client’s control.

• Devices which are connected to mobile VPN can communicate with one another using VPN port.

• It is necessary to fill in credentials for successful activation of the session. While it is not necessary to fill the APN fields at times.


There are a dozen combinations that are used to issue an IP address. After setting up the quick network registration process, the device then gets access to the computer, and the computer gets connected with the device. Similarly, the user is isolated with all others who are not connected to the client. All traffic is sent over the client’s own network, making it anonymous and accordance with the client’s internal policies.

Image Credits: VPN for Mobile from MaximP /Shutterstock

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