Wikipedia:Reference desk/Archives/Computing/2013 October 22

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October 22

Can websites get (or record) my MAC address if I visit them?

I'd like to know whether MAC address is transmitted to the website I visit.--124.172.170.233 (talk) 01:59, 22 October 2013 (UTC)

Your MAC shouldn't be visible outside of your LAN, as far as I recall (I'll dig up a source in a bit for that). If you're worried about the ability of a website to identify you, though, there are a number of other factors to consider. Also, an installed program can get your MAC, so if you have to install anything to use a site, they may be able to get a hold of it, then.Phoenixia1177 (talk) 04:12, 22 October 2013 (UTC)

(ec) If there is at least one router between your host and the server - which is nearly always true on the Internet, then it is not possible to deduce your MAC address from the IP address you are using. However, we cannot in general know what is transmitted to a website: it is up to your web browser to decide what data to transmit to the server. For standard HTTP traffic - which is the ordinary application-layer protocol used to browse websites - there is no reason to collect or transmit your MAC address. But, your browser, or a client plug-in, could choose to collect and transmit your MAC address to a server for some reason; nothing technically prevents this from happening, unless your operating system prevents those application software from determining your hardware address by sandboxing them. Nimur (talk) 04:42, 22 October 2013 (UTC)

And what if 'my MAC address' is not 'my computer MAC address' but 'my router MAC address'? Can websites see the latter? — Preceding unsigned comment added by 46.37.69.120 (talk) 11:42, 22 October 2013 (UTC)

I'm not quite sure what you're asking but to explain what Nimur is saying. Your router will know your computers MAC address and your computer will know your router's MAC address. The server or router that your router is directly connecting to will know your router's MAC address. This will generally be a gateway your ISP controls or in the case of a wifi hotspot, the AP. (In other words, your ISP, which in the case of an access point is who ever's in charge of the AP will know the MAC address of the device be it router or another device like a phone that's connecting to it.) Other servers further in the line will not intrinsically know your router's MAC addess but they will know who the MAC address of the server or router they're connecting to.

This is a fairly simplified explaination primarily targetting a typical home user set up. And this is only what's necessary as part of the ethernet protocol. It's possible something on your computer could reveal your MAC address to anyone else presuming the software knows what it is. Several game anti cheat software definitely do so. AFAIK they only generally reveal your MAC address although there's nothing stopping them revealing your router's MAC address as well, presuming they aren't prevented from knowing it by your operating system.

Note that one way of IPv6 auto configuration (IPv6 address#Modified EUI-64) [1] will put your MAC address in to your IP address. If you use this method, then anyone who knows your IP (i.e. anyone you connect to) can work out your MAC address. Of course they can't be sure you're realling using this method.

Incidentally, if you're worried for privacy reasons, unless you're very careful in what you do, e.g. how you set up your browser, what browser you use, what you do on the internet etc, you're probably failing to see the forest from the trees if you're worried about others knowing your MAC address.

Nil Einne (talk) 12:47, 22 October 2013 (UTC)

PPPoE routers have a MAC for the WAN port, but I don't believe PPPoA ones have anything comparable. -- Finlay McWalterჷTalk 12:51, 22 October 2013 (UTC)

Good point, if you're connecting with a protocol like ATM (e.g. using PPPoA) or for that matter a dialup modem or even a most mobile phone data networks (not wifi); rather than using ethernet, a MAC address it not part of the protocol so it will not be known the your ISP (whoever your connecting to). Some of these may have their own unique identifiers, e.g. the IMEI if you're connected to a mobile network. Nil Einne (talk) 13:04, 22 October 2013 (UTC)

If you are using IPv6 your mac address may appears as part of or IP address. Graeme Bartlett (talk) 21:00, 22 October 2013 (UTC)

Using Color Shading in Excel

Is it possible to have Excel (2010) automatically shade a cell with a pre-set color, depending on the numerical value of the cell?

Here is the example: I have a column of numbers.

• If the number in a cell is between 0 and 20, I manually go in and shade that cell red.
• If the number in a cell is between 20 and 40, I manually go in and shade that cell orange.
• If the number in a cell is between 40 and 60, I manually go in and shade that cell yellow.
• If the number in a cell is between 60 and 80, I manually go in and shade that cell green.
• If the number in a cell is between 80 and 100, I manually go in and shade that cell blue.

So, rather than me having to go in and manually shade each cell, is there a way that I can have Excel (2010) do this task automatically? Thanks! (Joseph A. Spadaro (talk) 14:35, 22 October 2013 (UTC))

You should be using conditional formatting - it's under the Home ribbon and is fairly self explanatory. This site explains it briefly, and there are links to further explanations. To do exactly what you have described you would need to click "new rule" for each case and enter the limits and the desired colour. 80.254.147.164 (talk) 14:51, 22 October 2013 (UTC)

Thanks, I will try that. I remember trying to use "conditional formatting" in the past, and it did not seem to fit what I needed. I will try what you suggest. Thanks! Joseph A. Spadaro (talk) 15:11, 22 October 2013 (UTC)

Yes, I tried (once again) to play around with conditional formatting. But, I can't seem to figure out how to do what I want. The only thing that I can get it to do for me is to provide various "shades" (gradients) that grow from light to dark in color, depending on how small or large the value is. For example – using the numerical and color scheme that I listed above – a value of 80 or 85 would yield a light blue; a value of 90 would yield a medium blue; and a value of 95 or 100 would yield a dark blue. But, I don't want graduated color shades; I just want the direct colors listed above. So, in other words, a cell with an 80 in it should have the same exact color shading as a cell with a 100 in it; namely, the same exact shade of blue. Can anyone help? Thanks. Joseph A. Spadaro (talk) 19:52, 22 October 2013 (UTC)

Apply multiple Highlight Cells Rules to the range of cells, each applying a different background shade. 86.147.202.194 (talk) 21:27, 22 October 2013 (UTC)

Perfect. That did it! Thanks so much to all of you. I really appreciate the help! Thanks. Joseph A. Spadaro (talk) 03:56, 23 October 2013 (UTC)