An Access Point Name (APN) is the name of a gateway between a GSM, GPRS, 3G, and 4G mobile network and another computer network, frequently the public Internet.
A mobile device making a data connection must be configured with an APN to present to the carrier. The carrier will then examine this identifier to determine what type of network connection should be created, for example: which IP addresses should be assigned to the wireless device, which security methods should be used, and how, or if, it should be connected to some private customer network. (Wikipedia)
Android AT&T APN Settings
- Open the Access Point Names or APNs menu.
- In Settings, look under Wireless & Networks or tap the Connections tab.
- Touch Mobile network. You may need to touch More settings, More…, or More networks first.
- Touch Access Point Names.
- Touch the AT&T APN if one is available. If not, press the Menu key and touch the new APN.
- Verify and update the following settings for the Data AT&T APN.
- Name: NXTGENPHONE
- APN: NXTGENPHONE
- Proxy: <Not set>
- Port: <Not set>
- Username: <Not set>
- Password: <Not set>
- Server: <Not set>
- MMSC: http://mmsc.mobile.att.net
- MMS proxy: proxy.mobile.att.net
- MMS port: 80
- MCC: 310
- MNC: 410
- Authentication Type: None
- APN Type: default,mms,supl,hipri
- APN Protocol: IPv4
- APN roaming protocol: IPv4/IPv6 or IPv4 only when roaming internationally
- Turn APN on/off: Grayed out unless there are multiple APNs
- Bearer: Unspecified
- Press the Menu key.
- Touch Save.
- Select the APN Profile that was just created. Restart your phone if the connection didn’t reset.
Visit AT&T for more details