How to Find the IP Address of an Email Sender

This article explains how to find a sender's IP address in an email that you've received. The info you need is found in the email message's headers.

How to Find IP Addresses in Email Headers

Modern email clients often hide the headers from view. However, headers are always delivered along with the message contents. Most email clients provide an option to enable the display of these headers if desired.

Internet email headers contain several lines of text. Some lines are labeled Received followed by the IP addresses of the sender's email server (from) and the receiving email server (by), as in the following example:

Received: from teela.mit.edu (65.54.185.39)
by mail1.aol.com with SMTP; 30 Jun 2003 02:27:02 -0000

These lines of text are automatically inserted by email servers that route the message. If only one Received line appears in the header, you can be confident this is the actual IP address of the sender.

Understanding Multiple 'Received' Lines

In some situations, however, multiple Received lines appear in an email header. This happens when the message passes through multiple email servers. Some email spammers insert additional fake Received lines into the headers to confuse recipients.

Identifying the correct IP address when multiple Received lines are involved requires a bit of detective work. If no faked information was inserted, the correct IP address is contained in the last Received line of the header. This is a simple rule to follow when looking at mail from friends and family.

If faked header information was inserted by a spammer, different rules are applied to identify a sender's IP address. The correct IP address isn't contained in the last Received line because information faked by a sender appears at the bottom of an email header.

To find the correct address:

• Start from the last Received line and trace the path taken by the message by traveling up through the header.
• The by location listed in each Received line should match the from location listed in the following Received line.
• Disregard any entries that contain domain names or IP addresses that don't match the rest of the header chain.
• The last Received line containing valid information contains the sender's true address.

Internet Email Services and IP Addresses

Popular internet-based email services differ in their display of IP addresses in email headers. Use these tips to identify IP addresses in such emails.

• Google Gmail omits the sender's IP address from all headers. Instead, only the IP address of the Gmail mail server is shown in the Received line.
• Microsoft Outlook.com provides the IP address in the first Received header line.
• Emails from Yahoo contain the sender's IP address in the last Received entry.