Most Internet Cafes utilize DHCP to dynamically provide a wireless client with an IP address for that session.
DHCP is a protocol used by networked computers (clients) to obtain IP addresses and other parameters such as the default gateway, subnet mask, and IP addresses of DNS servers from a DHCP server. It facilitates access to a network because these settings would otherwise have to be made manually for the client to participate in the network.
You Mac's AirPort, in turn, is set up to be a DHCP client by default. This allows your Mac to accept the dynamically provided IP address information from the Internet Cafe's DHCP server.
The reason I ask so many questions is that I can connect to the internet with my Airport Express base station network at home but not in my local WiFi cafe.
It sounds like the AirPort settings that your Mac is using is no longer at their default settings...and my be the reason you cannot connect to the Internet at the Cafe...or, the Cafe has additional settings required. I suggest that you check with the Administrator of the particular Internet Cafe you're having trouble connecting with to find out what settings are necessary to use their wireless network.
A typical AirPort is set up as follows:
System Preferences > Network > Show > Network Port Configurations
- Verify that AirPort is "On" (checked)
- Verify that AirPort is at the top of the list. If it isn't, you can drag it to the top.
Systems Preferences > Network > Show > AirPort
AirPort tab
- By default, join: Automatic
TCP/IP tab
- Configure IPv4: Using DHCP
- Configure IPv6: Automatically or Off
Proxies tab
- Configure Proxies: Manually
- Select a proxy server to configure: <All proxies should be unchecked unless you specifically require a proxy for Internet access.>
- Exclude simple hostnames (unchecked)
- Bypass proxy settings for these Hosts & Domains: <leave blank>
- Use Passive FTP Mode (PASV) (checked)
