The short answer to your question is no, your ISP can’t determine which of your emails are being read.
For all the things that your ISP can track, there’s a surprising number of things that it just can’t.
Ultimately, the capabilities of an ISP (or in this case, your email service provider) will vary dramatically depending on what they choose to do, what technology they happen to use, and how long they keep the information. In general, though, they probably can’t tell which specific emails have been read.
To show you what I mean, let’s go down this path a bit.
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What an ISP can tell you
What an ISP can tell is whether someone logged into your email account and from which IP address, but that’s about it. They can’t tell which messages were read – just that somebody was here.
And yes, your ISP will have the IP address, but they’re probably not going to tell it to you willingly. Most email providers simply do not make this information available. You’ll need legal authority of some sort. Depending on where you live, email providers will probably make it available to law enforcement if:
- They actually have the information to give.
- Law enforcement gives them a warrant, the appropriate legal documentation, or the rationale that justifies why they are legally entitled to this information.
And unfortunately, “I think someone is reading my email” doesn’t make the priority list.
The only exception, of a sort, is Gmail. They actually display a list of the ten most recent IP addresses in the lower corner of the Gmail web interface. These are potentially valid even if the email account is accessed via POP3, IMAP or the web.
What an IP address tells you
Even if you could get an IP address, it’s still not going to tell you what you need. You still need to trace it. Remember, the IP address is simply the IP address of a device connected to the internet. That device could be a single computer, or a router behind which are a handful, a hundred or a thousand different computers and as many people using them. The IP address may not actually represent a single person, and may well be used by many different people simultaneously.
Now, if the IP address owner kept the information relating to what connections to what computers were being made and when, then they might be able to tell you who used it and when. But to even find that information, you need more legal paperwork that explains why you’re entitled to this information.
And even if the IP address does point to a single location or person, that information is not publicly available – you’ll still need the legal authority to get an ISP or other entity to tell you who is at the other end.
In the end, there’s just no way to know. The short answer is what you’re looking for – the IP address – just isn’t useful to you.
What you can do instead
If you really suspect that somebody is reading your email, treat it like a hacked account. Change your password ando all of the things that my article “Email hacked: 7 things you need to do now” talks about. That’s the best way to secure your email.
If you’re still worried about people reading your email, then the only solution that I’m aware of is that you need to start encrypting your email. That means you only send encrypted email and you need to have people send you only encrypted email. That’s the only way to keep email completely secure.
Finally, I do want to address that one question you asked: deleting emails doesn’t matter. As we’ve seen, the email providers aren’t typically looking at message-level access. They typically don’t have that kind of information, especially not for POP3 accounts. All that they’re seeing is account level access. Whether you delete emails or not, it doesn’t really make a difference.