An email sender's IP address is the Internet Protocol address that identifies the network location of the sender. The email sender's IP address can be found in email headers, which are visible when you open an email in its raw form. To find an email sender's IP address, open the email and look for the "Received" fields in the email header. These fields show each server that handled the email along its route from sender to recipient, and contain the IP addresses of those servers. The first "Received" field usually contains the email sender's original IP address.