An APN, or access point name, is the setting that tells your phone how to reach your carrier’s data network. Apple’s definition is the shortest one going: “The APN defines the network path for all cellular data connectivity.” Without a working APN your phone can still call and text, but mobile data and picture messages stop.
Most people never see it. The phone reads the right APN from the SIM, or the carrier sends it. You only meet APN settings when that fails, which usually means you brought a phone from one carrier to another.
What the APN does
It names the gateway between the mobile network and the internet, and it carries the rules for that connection. Android’s developer documentation describes it this way: “A carrier uses the name, type and other configuration in an APNSetting to decide which IP address to assign, any security methods to apply, and how the device might be connected to private networks.”
One carrier can run several APNs. AT&T, for example, tells 5G phones to use one and LTE phones another. That is why copying a friend’s settings does not always work, even on the same carrier.
The fields in an APN, and which ones matter
An APN screen on Android has a dozen or more fields. Carriers leave most of them empty. These are the ones that do something.
| Field | What it is |
|---|---|
| Name | A label for you. It has no effect on the connection |
| APN | The access point’s name. This is the one value that must be exact |
| MMSC | The address of the carrier’s picture-message server |
| MMS proxy and MMS port | A relay some carriers put in front of that server |
| MCC and MNC | The country code and network code that identify the carrier |
| APN type | Which kinds of traffic this APN may carry |
| APN protocol | Whether the connection uses IPv4, IPv6 or both |
| Proxy, Port, Username, Password | Usually empty. Fill them only if your carrier says so |
When a carrier’s page says “Not set” or “blank” for a field, leave it empty. Do not type the words.
What is APN type?
APN type is a list of the jobs an APN is allowed to do. The values are
separated by commas with no spaces, as in default,supl,mms. Android defines
each one:
| Value | What Android uses it for |
|---|---|
default | Default data traffic. This is your normal internet connection |
mms | MMS traffic, meaning picture and group messages |
supl | SUPL assisted GPS, which helps the phone find its location faster |
dun | DUN traffic, used when the phone shares its connection |
hipri | HiPri traffic |
fota | The carrier’s portal for over-the-air updates |
ims | IMS, the system behind calls over LTE and Wi-Fi |
The names and their purposes follow Android’s ApnSetting reference.
The practical point is simple. If mms is missing from the type, picture
messages fail while the web still works. If default is missing, it is the
other way round. Use the exact list your carrier gives. T-Mobile publishes
default,supl,mms. AT&T publishes default,mms,supl,hipri.
When should you change your APN?
Rarely. Change it when all of these are true: you are using a phone that did not come from your carrier, mobile data or picture messages do not work, and a restart and a network settings reset did not help.
Do not change it to make data faster. An APN chooses the route. It does not change your plan’s speed or allowance.
Where the setting lives
On Android it is called Access Point Names, and it sits in the mobile network settings. T-Mobile’s instructions say to look in Settings “under Wireless & Networks or choose the Connections tab”, then Mobile network. The exact path differs between phone makers.
On an iPhone, Apple says the screen is Settings, Cellular, Cellular Data Network, and that you can view or edit it only “if your carrier allows it”. Many carriers do not, and then the screen is missing.
Settings by carrier
Use your own carrier’s values, from its own page. We keep them for T-Mobile, AT&T and Verizon, and for MVNOs such as Mint Mobile, Tello and US Mobile, with more carriers in the APN settings section.