Q: I have an iPod touch. When I am connected to a wireless network, what information does the iPod touch provide to the network router or switch? For example, can the network administrator see the name or serial number of the touch?
A: The iPod touch works as a standard wireless client in the same way as any computer does. In order to “lease” an IP address from your network, it will need to provide information such as the hardware address of it’s wireless card (sometimes referred to as a “MAC address”—short for “Media Access Control” and not to be confused with a Macintosh computer). An experienced network administrator might recognize this address as belonging to hardware manufactured by Apple, but it would otherwise be indistinguishable from an address belonging to any Mac hardware such as a MacBook or MacBook Pro.
If you have manually specified a “Client ID” in your network settings, this is also passed to the network server that provides your device with its IP address. However, this field is normally empty by default on the iPod touch and iPhone. Some networks may require it to be specified, but this is relatively uncommon.
Ultimately, however, information such as the iPod’s serial number or even the device name is not passed to the wireless network, and is not even available from the device itself on a standard non-jailbroken iPod touch configuration.
Deep scans of the device over the network by a very experienced networking engineer might reveal that the device is an iPod touch, but that’s pretty much it.
Note that jailbreaking the device and adding applications can expose your device, however, particularly if you’re adding file-sharing related applications. Such applications will generally make the iPod touch appear as a “server” on the network. In fact, many jailbreaking tools offer the ability to install OpenSSH on your device, which effectively makes it accessible to anybody with an SSH client and the correct password.