APN Settings Glossary

An Access Point Name is a text string that tells your phone which gateway server to route mobile data through. Think of it as an address label — without the correct one, your phone doesn't know how to reach the internet over your carrier's network.

Every UK mobile network uses a different APN value. EE uses everywhere, O2 uses mobile.o2.co.uk, and giffgaff uses giffgaff.com. Getting the APN exactly right — including correct capitalisation — is the single most important step in fixing mobile internet problems.

→ See What is an APN? — full explainer

A comma-separated list of services the APN handles. Common values are default (mobile data), mms (picture messages), and supl (GPS assistance). Most carriers want you to enter default,supl,mms so a single APN handles everything.

If you set APN Type to just default, you might find that picture messages stop working even though regular data is fine — because your phone has no APN configured for MMS traffic.

Controls how your phone authenticates with the carrier's gateway when connecting. The main options are None (no credentials needed), PAP (Password Authentication Protocol — credentials sent in plain text), and CHAP (Challenge Handshake Authentication Protocol — credentials verified via encrypted challenge).

Most UK networks use None. O2, giffgaff, Lycamobile, and a handful of others require PAP with a username and password. Setting Authentication to None when PAP is required — or vice versa — is a common cause of connection failures.

A more secure alternative to PAP for APN authentication. Instead of transmitting your password directly, the network sends a random challenge, and your phone responds with a cryptographic hash that proves it knows the password without revealing it.

In practice, no major UK consumer carrier currently requires CHAP — you'll only encounter it on enterprise or M2M (machine-to-machine) SIM configurations. If you see it as an option in your APN settings, leave it on PAP or None as instructed by your carrier.

The first generation of mobile data, launched in the early 2000s and branded as 2.5G. It was the original technology that required APN configuration, which is why APN settings still bear the naming conventions from that era.

GPRS itself is largely obsolete — most UK networks shut down their 2G data infrastructure or use it only as a fallback — but the APN settings screen on every Android phone still exists in exactly the same form because the underlying mobile data architecture hasn't fundamentally changed.

A network architecture framework that delivers voice, video, and messaging services over an IP data connection. On your phone, you'll see ims as one of the APN types — it's the channel used for VoLTE (Voice over LTE), which lets you make phone calls over 4G rather than the old circuit-switched network.

You should never need to manually configure an IMS APN. It is always provisioned automatically by the carrier via SIM card settings. If you see it in your APN list, leave it untouched.

The older 32-bit internet addressing system that produces addresses like 192.168.1.1. Setting your APN Protocol to IPv4 forces your mobile data connection to use only this version. It works on all networks and is the most broadly compatible option.

The downside is that IPv4 addresses are running out globally, so carriers increasingly prefer dual-stack connections. Unless you're experiencing specific connectivity problems, set the Protocol to IPv4/IPv6 for best results.

The successor to IPv4, using 128-bit addresses (e.g. 2001:0db8:85a3::8a2e:0370:7334) to provide a virtually unlimited number of unique addresses. All four major UK networks — EE, O2, Vodafone, and Three — support IPv6 on their 4G and 5G infrastructure.

For APN configuration, you typically set the Protocol field to IPv4/IPv6 (dual stack) rather than IPv6 alone. Pure IPv6-only connections can cause problems with older apps and websites that haven't yet adopted the new protocol.

The technical standard marketed to consumers as 4G. LTE brought a significant jump in mobile data speeds over the preceding 3G (HSPA) networks. The successor, LTE Advanced (LTE-A), is sometimes labelled 4G+ or 4.5G.

APN settings work identically across 3G, LTE, and 5G — you don't need separate configurations for different network generations. The same APN that works on 4G will work on 5G with no changes required.

A three-digit number that identifies which country a mobile network operates in. The United Kingdom's MCC is 234, and this value is the same for every UK network — EE, O2, Vodafone, Three, and all MVNOs. You will never need to change the MCC when configuring APN settings on a UK SIM.

MCC and MNC together form the PLMN (Public Land Mobile Network) identifier that uniquely identifies a specific carrier in a specific country. Your phone reads these values from the SIM automatically; the APN settings field is just a confirmation.

The standard used for sending picture messages, video clips, and group texts between mobile phones. Unlike regular SMS text messages, MMS uses a separate data channel that requires its own set of APN configuration fields (MMSC, MMS Proxy, and MMS Port).

This is why you'll often see two distinct sections on the APN configuration screen — one for mobile data and one specifically for MMS. Getting the MMS settings wrong won't break your internet connection, but it will prevent picture messages from sending or downloading.

→ See MMS troubleshooting guide

The server your phone contacts to submit outgoing picture messages and retrieve incoming ones. It's entered as a full URL, for example http://mmsc.mms.o2.co.uk:8002 for O2 or http://mms/ for EE. Note that these are private carrier URLs — they are not accessible via a regular web browser.

If you leave the MMSC field blank or enter the wrong address, MMS messages will either fail silently or get stuck in your outbox indefinitely. The MMSC URL must match your carrier exactly, including the port number if one is specified in the URL itself.

A two-digit number that identifies a specific mobile network operator within a country. Combined with the MCC, it uniquely identifies every carrier globally. UK MNC values are: EE = 30, O2 = 10, Vodafone = 15, Three = 20.

MVNOs (virtual networks) inherit the MNC of the network they run on. So giffgaff, Sky Mobile, Tesco Mobile, O2, Virgin Media, and Lycamobile all use MNC 10 because they all use O2's infrastructure. Getting the MNC wrong in your APN settings can prevent the connection from activating.

An intermediary server that some carriers route MMS traffic through before it reaches the MMSC. It's entered as an IP address, such as 82.132.254.1 for O2 and its MVNOs. Not all carriers use a proxy — Three UK, for instance, uses a hostname (mms.three.co.uk) rather than an IP address.

If a proxy is required and you leave this field blank, MMS messages may fail even if the MMSC address is correctly configured. If no proxy is required, leave the field empty — entering a wrong proxy address is equally damaging.

The TCP network port number that your phone uses to connect to the MMS proxy server. Common UK values are 8080 (used by EE, O2, and their MVNOs) and 8799 (used by Vodafone, Three, and their MVNOs). The port must match what the proxy server expects, or the connection will be refused.

Note that the MMSC URL sometimes also contains a port number (e.g. :8002 at the end). The "MMS Port" field in your APN settings refers to the proxy port, not the MMSC port — these are separate values and both must be correct.

A basic authentication mechanism where your phone sends a username and password in plain text to authenticate with the carrier's APN gateway. Despite being relatively simple, PAP is widely used on UK mobile networks because the APN connection itself is already secured by the network's encryption.

Carriers that require PAP authentication include O2 (username: o2web, password: password), giffgaff (username: giffgaff, password: password), and Lycamobile (username: lmo, password: plus). On most phones you also need to set the Authentication Type field to PAP — simply entering the credentials without changing the auth type won't work.

The IP version that should be used for the APN's data connection. Options are IPv4, IPv6, or IPv4/IPv6 (dual stack). The recommended setting for all UK networks in 2025 is IPv4/IPv6, which allows your phone to use either version depending on what the server supports.

This field is separate from the Roaming Protocol, which applies only when your phone is connected to a foreign network abroad. Both should normally be set to IPv4/IPv6 unless your carrier specifies otherwise.

The IP version used when your phone connects via a foreign network while you're abroad. This field is functionally identical to the Protocol setting but applies only during international roaming. Set it to IPv4/IPv6 to match your home Protocol setting unless your carrier advises otherwise.

Some phones only show this field if roaming is enabled. On others it appears regardless. Leaving it blank or set to a different value from Protocol shouldn't affect your domestic data connection, but can cause issues when travelling internationally.

A protocol used for Assisted GPS (A-GPS) that speeds up location fixes by downloading satellite data (ephemeris) over the mobile data connection rather than waiting to receive it directly from GPS satellites, which can take several minutes from cold start.

SUPL is included in the APN Type field alongside default and mms — the full recommended value is default,supl,mms. You don't configure a separate SUPL APN on most phones; including supl in the APN type list tells the system to use the same APN for location assistance data.

A protocol used for managing supplementary telephony services — such as call forwarding, call barring, and voicemail preferences — by sending and receiving XML documents over an HTTP connection. On some phones you'll see xcap listed as an APN type, sometimes in a carrier-configured APN that you cannot edit.

You should never need to manually set up an XCAP APN. Carriers that use XCAP provision it automatically via the SIM card. If you accidentally delete a carrier-configured APN that includes the xcap type, you may lose the ability to manage certain call settings until you restore it or contact your carrier for the correct configuration.