I'm posting on HN to get the low down if anyone who has ACTUALLY first hand know how on how this is accomplished.
How does Starbucks knows how to grab my MAC Address?
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Re: How does Starbucks knows how to grab my MAC Address?
#2If you are on their network then they can see your MAC address. That's how Ethernet works.
See http://en.wikipedia.org/wiki/MAC_address#Spying for an example of how Apple has changed iOS so it uses a random MAC address. See also http://security.stackexchange.com/questions/6868/randomizing... .
Re: How does Starbucks knows how to grab my MAC Address?
#3Re: How does Starbucks knows how to grab my MAC Address?
#4Re: How does Starbucks knows how to grab my MAC Address?
#5The wifi router knows your mac and probably intercepts a HTTP request (like a "captive portal"), which probably redirects you to that URL while including the MAC address
Re: How does Starbucks knows how to grab my MAC Address?
#6That web site for me says "Looks like you might be outside a Starbucks store / Our local store web site is only available when you’re connected to Wi-Fi at most U.S. Starbucks stores." If you are on their network then they can see your MAC address. That's how Ethernet works. See http://en.wikipedia.org/wiki/MAC_address#Spying for an example of how Apple has changed iOS so it uses a random MAC address. See also http:/…
Re: How does Starbucks knows how to grab my MAC Address?
#7The wifi router knows your mac and probably intercepts a HTTP request (like a "captive portal"), which probably redirects you to that URL while including the MAC address
Yes, I am connected to the store's wifi. Can you point me to some code that actually can grab the mac address? As the title suggests -- I want to know how they do it.
What you're asking is, in essence, "how does ethernet work?" That cannot be explained in a few paragraphs. You can start with Richard Stevens' "TCP/IP Illustrated, Vol. 1", as one of many available descriptions. You can use Wireshark to track all of the details.
At this point you should stop asking questions here. There's likely no simple answer, and this is a great chance to experiment and figure it out for yourself.
(Even if someone knows the exact details of how Starbucks does it, you are unlikely to understand the explanation without understanding some of the fundamentals.)
Re: How does Starbucks knows how to grab my MAC Address?
#8That web site for me says "Looks like you might be outside a Starbucks store / Our local store web site is only available when you’re connected to Wi-Fi at most U.S. Starbucks stores." If you are on their network then they can see your MAC address. That's how Ethernet works. See http://en.wikipedia.org/wiki/MAC_address#Spying for an example of how Apple has changed iOS so it uses a random MAC address. See also http:/…
Yes, I am connected to the store's wifi. Once I am on their network, how do they actually grab it? What headers names do they inspect for, etc. I'd like to actually know the implementation details and code sample. I looked everywhere on Stackeroverflow and can't find anyone who has done this.
Note: the above is a 10,000 foot observation of what happens.
More in-depth: https://en.wikipedia.org/wiki/MAC_address
Re: How does Starbucks knows how to grab my MAC Address?
#9That web site for me says "Looks like you might be outside a Starbucks store / Our local store web site is only available when you’re connected to Wi-Fi at most U.S. Starbucks stores." If you are on their network then they can see your MAC address. That's how Ethernet works. See http://en.wikipedia.org/wiki/MAC_address#Spying for an example of how Apple has changed iOS so it uses a random MAC address. See also http:/…
Yes, I am connected to the store's wifi. Once I am on their network, how do they actually grab it? What headers names do they inspect for, etc. I'd like to actually know the implementation details and code sample. I looked everywhere on Stackeroverflow and can't find anyone who has done this.
What they will likely do is take your IP and look to which MAC their DHCP-Server has assigned that IP to. There are other possibilities though, but they are more complicated (using ARP-cache or requests, doing a raw packet dump at the webserver).
If you want learn more, I think you could read a bit about the different layers first, and then read about how ethernet, IP/ARP and DHCP work. There are likely no "headers" (I assume you mean HTTP-headers) they inspect.
Re: How does Starbucks knows how to grab my MAC Address?
#10Earlier quoted context omitted.
Yes, I am connected to the store's wifi. Can you point me to some code that actually can grab the mac address? As the title suggests -- I want to know how they do it.
http://en.wikipedia.org/wiki/Captive_portal lists three ways to achieve it. The details will depend on how Starbucks decided to do it. What you're asking is, in essence, "how does ethernet work?" That cannot be explained in a few paragraphs. You can start with Richard Stevens' "TCP/IP Illustrated, Vol. 1", as one of many available descriptions. You can use Wireshark to track all of the details. At this point you shou…