Pictures Embedded In Emails

Hello--

I am switching from Outlook Express to Thunderbird, and did not have T-Bird migrate in the emails that are on OE. I just checked OE to see if it was still getting mail that I have enabled T-Bird to receive, and happened to notice the following message on a bar over the email that was highlighted.

"Some pictures have been blocked to help prevent the sender from identifying your computer. Click here to download pictures."

Does that mean that anytime someone sends me an email with pictures in it, and I simply open the email, and those pictures are not blocked by my email client, that whoever happens to send me an email with pictures in it can identify my computer?

And a companion question -- what is it they could identify, my MAC address or my IP address or both?

Thanks in advance.

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alexcrist

Hi Carol,

I have never heard about anything like this. Could you post a screenshot to be sure I understood completely what you mean?

About your question... I suppose it could be possible. In an internet connection, the sender always has to know the IP of the receiver, so that it knows where to send the data. (just like when you send a postcard...if you don't know the address of the person you want to send the postcard to, you can't send the postcard, can you? ). So, if those images were not attached to the e-mail, and they were only hot-links to images on certain servers, the "people on the other end" can (and have to) find out your IP.

About the MAC address...I don't know if it can be identified in this manner.

Also, most times, you have absolutely nothing to worry about. As I said, the server has to know your IP so that the connection works (it's perfectly normal). Only if that e-mail is a SPAM/PHISHING e-mail, then I guess this info might be used to find out which addresses are real, and which are fakes (if you connect to their server to download the images, then your e-mail is active and they will continue to send you SPAM).

Bottom line: if the e-mail is legit, you have nothing to worry about. Just set your e-mail client to show the images. If the e-mail is SPAM, just don't open it in the first place (it might contain something more then just simple images... something like worms/viruses/ etc...)

I hope I answered your question

Cris.

C-1000

Hi Carol,

I have never heard about anything like this. Could you post a screenshot to be sure I understood completely what you mean?

About your question... I suppose it could be possible. In an internet connection, the sender always has to know the IP of the receiver, so that it knows where to send the data. (just like when you send a postcard...if you don't know the address of the person you want to send the postcard to, you can't send the postcard, can you? ). So, if those images were not attached to the e-mail, and they were only hot-links to images on certain servers, the "people on the other end" can (and have to) find out your IP.

About the MAC address...I don't know if it can be identified in this manner.

Also, most times, you have absolutely nothing to worry about. As I said, the server has to know your IP so that the connection works (it's perfectly normal). Only if that e-mail is a SPAM/PHISHING e-mail, then I guess this info might be used to find out which addresses are real, and which are fakes (if you connect to their server to download the images, then your e-mail is active and they will continue to send you SPAM).

Bottom line: if the e-mail is legit, you have nothing to worry about. Just set your e-mail client to show the images. If the e-mail is SPAM, just don't open it in the first place (it might contain something more then just simple images... something like worms/viruses/ etc...)

I hope I answered your question

Cris.

Well, the server is one thing, but the "sender" is another. For instance if I send an email to you, my server would have to recognize and be able to transmit it to your server. But the caution message said "help prevent Sender from identifying your computer."

As I recall, Thunderbird has some sort of similar thing where if I get an email with photos embedded in it, it will show me the text but there will be little boxes with red X inside them, showing an image is suppressed. I haven't worked with T-bird long enough to remember if there's a "click here" to enable the pictures to be shown (hence I assume downloaded).

How do I send or post a screen shot? I did one with Cntrl+Alt+PrintScreen and pasted it into a Word doc but I don't think that's what you meant. Or is that how it's done? Also if the screen shot contains personal info (e.g., my email address) and I don't want to post it on a public forum, how would I send it to you?

alexcrist

Hi Carol,

Whe I said Sender and Receiver, I didn't mean the sender/receiver of the e-mail. I meant the sender/receiver of data... that means the server (sender: it sends data to you) and your PC (receiver: you receive the data from the server).

Also, the sender of the e-mail has nothing to do with the server on which the images are located. Maybe those images are stored on public servers (like image upload servers, or business servers...), or on personal servers (like the one I have on my PC). But this server may be or may not be the same server as the one that sent you the e-mail.

About the message that said "help prevent Sender from identifying your computer."... well, that's just a generic message. In that message, the Sender is actually the person who sent you the e-mail (and which might be watching you).

As I said, if that e-mail is legit (you know where it came from), then it's safe to view the images. Otherwise, the warning might be true.

Also, keep in mind that finding out an IP address means nothing. As I previously said, everyone you talk to "knows" your IP (even the persons you talk to when you use Yahoo!Messenger). That's irrelevant, because it's absolutely normal. If you have a firewall to protect you, you're safe It's not like an advanced hacker will try to break into your PC (in which case, he wouldn't bother to send you an e-mail with images to find out your IP)

How do I send or post a screen shot? I did one with Cntrl+Alt+PrintScreen and pasted it into a Word doc but I don't think that's what you meant. Or is that how it's done? Also if the screen shot contains personal info (e.g., my email address) and I don't want to post it on a public forum, how would I send it to you?

Yes, that's what I mean. If you don't want to post it on the public forum, just send me a PM and attach the image to it.

Cris.

C-1000

Yes, that's what I mean. If you don't want to post it on the public forum, just send me a PM and attach the image to it.

Cris.

Thanks, I sent it to you.

alexcrist

Hi Carol,

I wasn't worried about CNET, but that generic message does seem to indicate that if you download whatever pictures are embedded in their email, some sender COULD identify your computer. (I take that to mean the actual sender of the email itself, not their server.)

OK. Just to be clear. The server is a PC. As I said, it needs to know your IP (in an e-mail's case, it needs to know your mail server's IP), so that it can send you data. Because the server is a machine, it cannot do anything to harm you (unless it was instructed to).

But, the server (the machine) can "tell" a person your IP. That person (maybe the actual sender of the e-mail) can choose to use that IP to try to hack into your PC (if you have a firewall, you're safe against these attempts) or just do nothing with that IP.

Since you say you trust CNET, then it's absolutely no problem in viewing their images. I believe that they won't try to use your IP against you.

So I was wondering how the sender of an email could identify anyone's computer just by sending them a picture that gets downloaded when they open the mail. And what that meant – ("identify your computer").

"Identify your computer" means finding out your IP (which, in the wrong hands, might be used to find personal data about you). The IP can be used to find personal data about you only if your ISP (Internet Service Provider) allows anyone to access their database. Generally, that's not possible.

Your IP can be found when you download the actual image. As I said, when you contact the server and "ask" it to send you the image, your PC sends along with the request your IP (so that the server can answer). This is how the server finds your IP.

A small example is this forum. If you look at all your posts, you'll see in the top-right corner your own IP address.

You just have to calm down. If someone finds out your IP, that someone can use it to compromise your PC. But that is a necessary risk. You cannot hide your IP.

Like the first example I gave in my first post (the one with the postcard): an IP is a PC's address. Just like you have a home address. If someone finds out your home address, he can rob you. To prevent that, you use a locked door at your home (and, for your PC, you use a firewall). You cannot hide your IP, just like you cannot hide your home address.

Cris.

C-1000

Hi Carol,

OK. Just to be clear. The server is a PC. As I said, it needs to know your IP (in an e-mail's case, it needs to know your mail server's IP), so that it can send you data. Because the server is a machine, it cannot do anything to harm you (unless it was instructed to).

But, the server (the machine) can "tell" a person your IP. That person (maybe the actual sender of the e-mail) can choose to use that IP to try to hack into your PC (if you have a firewall, you're safe against these attempts) or just do nothing with that IP.

Since you say you trust CNET, then it's absolutely no problem in viewing their images. I believe that they won't try to use your IP against you.

"Identify your computer" means finding out your IP (which, in the wrong hands, might be used to find personal data about you). The IP can be used to find personal data about you only if your ISP (Internet Service Provider) allows anyone to access their database. Generally, that's not possible.

Your IP can be found when you download the actual image. As I said, when you contact the server and "ask" it to send you the image, your PC sends along with the request your IP (so that the server can answer). This is how the server finds your IP.

A small example is this forum. If you look at all your posts, you'll see in the top-right corner your own IP address.

You just have to calm down. If someone finds out your IP, that someone can use it to compromise your PC. But that is a necessary risk. You cannot hide your IP.

Like the first example I gave in my first post (the one with the postcard): an IP is a PC's address. Just like you have a home address. If someone finds out your home address, he can rob you. To prevent that, you use a locked door at your home (and, for your PC, you use a firewall). You cannot hide your IP, just like you cannot hide your home address.

Cris.

Okay. I get it. Well, that little generic message sure raised some questions the way it's worded, LOL. But it's a good feature because if you did open a Spam or other bad email, then you would have to purposely tell it to download them. I usually tend to delete most things I don't recognize, but sometimes an email is questionable enough to open it.

Thanks, Cris.