How to be sure that the tethering is done using the proper APN (e.g. a private employee APN)

If you are going to use your smartphone (Android, iOS, Windows 10 Mobile) as an hotspot Wi-Fi when it is set in your device  an employee private APN, please take care to check that from a PC (connected to that hotspot) you can access the intranet and so be sure that the data traffic is going through that private APN and not on a public one (the charged one).

Unfortunately I realize that, even though I set, in a second time, the parameters available in the APN definition in the correct way, the change I did was not reflected in the Android Sony device I was using: therefore all the traffic I did with my PC, connected in tethering to that hotspot Wi-Fi, was still routed to the public APN and so charged (or at least decreased the plafond I have).

First of all the right setting of the APN you manually define must have the APN Type set to default,supl,dun (for Android smartphones, for other smartphones see below) BUT,  it could not be sufficient to have that setting if those parameters were inserted in a second time and not since the beginning when you manually defined the first time that APN.

As it can be easily found searching “default,supl,dun” with a search engine, this setting of APN Type in Android smartphones is quite common (at least in Italy) also for a consumer use of a public APN: in particular the default,supl activate the geolocation via IP and the dun let use the device as a modem to do tethering (see, for example, ;  – Dial-Up Networking referred to, this connection with the default connection is similar to a dial-up network bridge used to perform the carrier to know the application of the dial-up network traffic, this connection can be used simultaneously with the default connection …). Also at  this link you can find more information related to that setting …

Note that APNs let users connect their cellphones to a particular wireless provider’s network, while VPNs protect private information being sent over a public telecommunications network: so are different things and you do not need to set any VPN on your Windows 10 PC client while using the hotspot Wi-Fi of your smartphone where the an employee private APN is activated.

Therefore follows the following steps to be sure you are using the employee private APN while doing tethering (procedure for Android devices, but it can  be easily extended also for other ones):

  1. Check if the APN, you manually defined, has set the APN Type to default,supl,dun
  2. Connect the PC (or another device, may be another smartphone) to the hotspot Wi-Fi enabled on your smartphone while it is set to use the employee private APN. Be sure no other data connections are available (e.g. cable connection) on that client.
  3. Try to go with a client browser to your firm intranet: if you succeed, everything is all right and you are sure that all the traffic data goes through that APN. Otherwise, if you can navigate on that external device only on Internet (disabling a possible proxy setting on that PC) but not in intranet on that client, it means that the tethering still use the public APN (even though on your smartphone, using its browser, you continue to access the intranet and so its internal data traffic uses the firm APN). In that case you need to make a reset of the APN and then manually insert a new one, related to your firm, setting from the beginning the right values to the APN Type (that is default,supl,dun). To do a well done reset do the following step.
  4. To do a reset of the APNs,
    1. Switch off the phone,
    2. Take away the SIM,
    3. Switch on the phone,
    4. Go to the APN section and, clicking on the tre points at the upper right, select the voice menu “Reset default settings” in order to reset the APNs.
    5. Switch off the device and then
    6. Insert again the SIM and
    7. Switch on the device. Now you will have in the APN section only the APNs related to the network provider of the SIM (e.g. TIM WAP, TIM Web).
    8. Insert the new employee private APN being careful to set properly not only the name (whatever) and the endpoint, but also the APN Type (i.e. default,supl,dun).
  5. Connect to the hotspot, while that new APN is active, from a PC and then try to navigate in the intranet of your firm: now it should surely work and this prove that all the tethering traffic is going to the employee private APN! Take care to have the proxy set in the proper way in order to reach not only the intranet sites, but also the INternet one.


Clicking on the tre points at the upper right, select the voice menu in order to reset the APNs

Clicking on the tre points at the upper right, select the voice menu in order to reset the APNs

WP_20160823_09_35_36_Pro WP_20160823_09_35_27_Pro


If you are using an iPhone, from iOS9  (September 2015, then quite recently) they introduced in an APN configuration page, also a specific new section called Personal Hotspot (IT: “Hotspot personale”) where you can explicitly set the APN to be used for the tethering traffic … if you want that it will be the same set for the smartphone traffic you only have to set it the same:

iOS from vers. 9 has the Personal Hotspot section

iOS (from vers. 9) has the Personal Hotspot section



If you are using a Windows 10 Mobile (or a Windows Phone 8.1) unfortunately I think that this specific feature is not yet implemented so the tethering traffic goes to the selected public APN selected in the combobox (as defined by the SIM or branded phone)even though a hand configurated APN is defined and made active (only the traffic of the smartphone will use that selected APN). Note than same problem was proper of iOS before vers. 9 (September 2015, then quite recently). For more info on this topic see this other post I wrote some time ago …


P.S. For TIM employee there is a app developed by a colleague that allows to keep an eye on which APN you are using, you point out that the Android Widget ApnPreferito to display the APN to which you are connected.

It provides:

  • Icon of different colors if you are connected to the corporate network
  • Only widget to open APN/Wi-Fi settings and to turn on/off the Wi-Fi

If you are interested to get it, ask me more …


Questo post si aggiunge ad altri che sono specificatamente indirizzati a colleghi.🙂

PS: puoi trovare gli altri post filtrando, nella combobox a desta, sulla categoria “Aziendali”. Alcuni sono protetti da password per cui se ti interessano puoi contattarmi tramite l’email aziendale o telefonicamente.




Informazioni su Enzo Contini

Electronic engineer
Questa voce è stata pubblicata in Aziendali, Review e test, Smartphone OS. Contrassegna il permalink.

Una risposta a How to be sure that the tethering is done using the proper APN (e.g. a private employee APN)

  1. Pingback: Cosa fare se connettendo un PC all’hotspot Wi-Fi del proprio smartphone, su quest’ultimo si perde la connessione a Internet bensì venga fornita al PC | Enzo Contini Blog

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