Does my phone have an IP address?
In theory, if I am simultaneously logged in the SD (or any other site) on both my phone and my desktop computer, can someone who knows what to look at tell I’m logged in via two different devices?
Also if I were to log in from my laptop or tablet, presumably it would have a different IP address than my desktop? Or not? Or does it depend on the provider?
If it is connected to the Internet, yes.
Yes, although the two separate devices won’t necessarily have different public IP addresses if they are behind the same NAT gateway on a wireless network, for example. Nonetheless, they can be easily differentiated by their HTTP headers and separate session IDs.
It depends on how your network is set up, if we’re talking about WiFi. If we’re talking about something like 3G, your device will have a dedicated public IP while it’s connected.
Look at it this way: when your computer/phone/tablet/whatever sends a request to the SDMB saying “show me thread #621623,” the SDMB server needs to know where to send that information. In simplistic terms, this is the IP address. As friedo intimated, it’s possible for two devices to share an IP address through NAT (network address translation). This would put your phone and computer on the same IP address, but show different ports for the request.
Either way, the system can definitely tell you’re coming in from two places*. If it couldn’t, the server would not be able to get the page back to you.
- It can’t tell whether those two IP/port combos are actually two different physical devices. Sometimes I will access a site through two browsers at once (say, Firefox and Safari). These have different sessions, different shopping carts, and so on. One could be logged in and the other not.
Ah! Thank you very much.
Even though terms like NAT gateway and 3G whoosh over my head, I understand the two-browser analogy. I don’t like IE but often keep it open so I can have two separate gmail accounts open on my desktop simultaneously.