How to find out the IP address of email sender in Gmail

Question

Gmail doesn't give the IP address of the sender in its mail headers for security reasons. I'd like to know whether there is some other way of getting the IP address of the sender.

Since Gmail specifies the IP address of its email relay server, which the sender first contacts, is there any way of querying the relay server to get the IP address of the sender by specifying the unique Message-ID of that email? If so, please explain how is it done. And if not, is there any other method of getting the IP address?

Answer 1

There is no technical way to get the ip-address of someone sending an email via the gmail web interface. Google does not put it into the email headers. And there is no API to query gmail for it.

If you really need that IP address for valid reasons, you need to get a court order.

Answer 2

This can potentially be done through some sort of social engineering, if you can send an email back to the original sender and get them to click on a link in the email.

You need to set up a website which logs the visitor's IP address, then somehow make the person who sent you that email visit your site. This probably involves sending them an email and hoping they read the email and click a link in it.

A related approach is to send them a HTML email that contains an inline image hosted on your website. However, most email clients do not load linked images by default, precisely to protect the privacy of their users. Therefore, in most cases this will not work (unless the person just happens to have overridden the defaults in their email client).

Therefore, a more realistic approach is to send them an email containing a link, and hope they will click on the link.

Example PHP code to log the visitor's IP address (from http://www.binrev.com/forums/index.php/topic/20288-php-ip-logger/):

<?php
header('Content-type: image/jpeg');
readfile('image.jpg');
$filename = "logged.txt";
   $somecontent = "Connection from:".$_SERVER['REMOTE_ADDR']." at ".date("r",time())."\n";
   if ($handle = fopen($filename, 'a')) {
           fwrite($handle, $somecontent)
           fclose($handle);
   }
?>

Answer 3

GMail does send the IP-address in its mail headers: check the X-Originating-IP header.

Answer 4

To view the full headers of an email within the Gmail web interface, you need to select "show original" from the drop down 'More" actions menu on the right. The "show details" button next to the sender details only gives a subset of information, not the full headers.

I tested sending a message from the gmail interface and found there was no X-Originating-IP or any header which gives any sender IP details. This is no surprise. Note that the X-* headers are optional headers and not required by the SMTP protocol.

Even if there was sender IP information in the message, it is largely useless. This is especially the case if you are trying to use it to track someone down. Essentially, you are wasting your time.

1. Many users don't have static IP addresses. ISPs assign IP addresses from a pool of available IPs.

2. Many sites use NAT and other mapping techniques so that all hosts on their internal network have non-routable private IP addresses (i.e. 192.168.1.9), but a common public routable IP address.

3. Users can access Gmail from any Internet connected system which has a web browser, such as an internet cafe, public wireless networks, etc.

4. Many web connections pass through proxies. From the Gmail perspective, the IP the client is connecting from is the proxy IP, not the IP of the sender's PC

5. It is fairly trivial to fake an IP address

Even the suggestions of following a legal process, such as court orders forcing Gmail to provide log information etc is a waste of time. While, after much effort and probably significant cost, you may be able to get this information, it is largely pointless. At the end of the day, anybody can obtain a Gmail account under any name. You are not required to prove who you are. There is pretty much no level of assurance that a Gmail user is the person they claim to be. This is the case with many mail providers, not just Gmail. The whole mail environment is inherently flawed in this way and you cannot relay or guarantee anything regarding sender details or mail headers. As the old cartoon depicted, "On the Internet, nobody knows you're a dog".

If you are receiving abusive emails from a Gmail user, your best course of action is to report them to Gmail. They are usually pretty good at shutting down accounts of anyone who is abusing the service. Of course, there is no guarantee this person actually is a Gmail user — as already mentioned, the whole email ecosystem is flawed and it is trivial to make a message appear to be from someone.

Apart from that, all you can do is ignore it. Filter out the offending sender or just hit delete and move on.

Answer 5

Since we're on the topic of Gmail. There is a very simple answer. Select the "More options arrow" here --

Select "Show Original", a new window will open with a full HTML page including "sender" and "recipient" information. Looks kinda like this --

There you have it. :) And of coarse I've clipped the private information but you will see a full page when you execute this function.