The new iPhone firmware 2.x doesn’t allow users to edit the APN for some carriers. In the new iPhone 2.0 Apple gave service providers the ability to disable this setting so you’ll automatically connect to the Internet through their network and incur their data access fees. What this also means is that you wont be able to edit the APN if its set to something else and you wont be able to access the Internet on their network until you change the APN. This means even if you have an officially unlocked iPhone, you can’t access Internet if you are on the network of service providers who don’t allow editing the APN setting.

So editing APN is useful in both scenarios 1. Those who want to change the APN to be able to access Internet 2. Those who want to change the APN value to some random string to avoid the hefty data charges.

Generally APN can be easily edited by going to Settings>General>Network>Cellular Data Network. Here’s the official guide to view/edit APN settings for the carriers who do allow editing.

For those who don’t allow editing – there are 2 ways to do it:

1. For those who have officially unlocked iPhone (Not Jailbroken):
This is for people who have an officially unlocked iPhone (from Hong Kong, Singapore, Europe etc…) traveling to other countries and using a local sim on their unlocked iPhone. This is for users like me – I recently travelled to India (Bombay), i was using a local Vodafone sim card and wanted to change the APN so that i could use the Internet on my iPhone. Since my iPhone didn’t allow me to do so, i contacted the vodafone customer service and they were extremely clueless about the APN stuff – instead they advised me to get on a more expensive Internet data plan when i was already on a basic data plan. Knowing how clueless they were it was pointless to expect any help from them. Finally I figured out a way myself -

1. Download and Install the iPhone Configuration Web Utility – This is basically for the enterprise customers to help them deploy configurations within their organization.
2. After installation, open your web browser and access http://localhost:3000/ (Mac users – refer the guide)
3. Enter Username/Password – admin/admin
4. On the General tab – Edit Name, Identifier and Organization
5. Click on Advanced tab – Edit the Access Point Name (APN)
6. Back on the General tab click on Export Profile and save the configuration profile as a file
7. Email yourself the configuration file as an attachment and open it on your iPhone
8. Once you click on the attachment on iPhone it will prompt you about making configuration changes and warn you about no trusted signature, just click continue
9. Once installed you will be able to access Internet if you entered proper APN string in step 5 or you wont be able to access Internet if your purpose was to disable Internet and you entered a random string in step 5.

2. Outra forma:

Para aqueles que tem iPhone desbloqueado / jailbroken:

Pode se acessar o iPhone via SSH e editar o arquivo em carrier.plist que fica em:
/System/Library/Carrier Bundles/<Sua operadora>

Adicione o seguinte:
<key> AllowEDGEEditing </ key>
<true/>

logo após
<? xml version = "1.0" encoding = "UTF-8"?>
<! DOCTYPE plist PUBLIC "- / / Apple Computer / / DTD plist 1.0 / / EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
 
Uma vez feito isso, você conseguirá editar o APN em seu iPhone, indo em:
Ajustes> Geral> Rede> Rede de Dados Celular.