How can I find the source and purpose of emails originating from unrecognized IP addresses?

Email marketer from Stack Overflow explains that examining the full email header is crucial, looking for 'Received:' fields to trace the path and identify originating servers. They advise using online tools to parse and analyze these headers.

Email marketer from WhatIs.com shares the definition of Email Tracking. This is the technique of monitoring delivery of email messages in order to learn if a message was delivered, opened, and read; what email client was used; and, sometimes, from what geographical location.

Email marketer from EmailToolTester shares a list of email header analyzer tools. They advise copying the email header from the original email and then pasting it into the tool, that will then give you insights into its origin.

Email marketer from Reddit says the best way to prevent email spoofing is to make sure you have set up DKIM, SPF, and DMARC on your domain.

Email marketer from Reddit shares that checking the 'Return-Path' header can often reveal the actual sender's email address, even if the 'From' address is spoofed. They also recommend using IP lookup tools to investigate the IP address in the 'Received:' headers.

Email marketer from Mailjet Support explains that email headers contain routing information. They recommend using a header analyzer tool to decode the headers, making it easier to identify the sending server's IP address and other relevant data.

Expert from Spam Resource explains the method of querying various blacklists to see if an IP address is listed. If it is, the listing notes will usually provide some insight as to the reasons it was blacklisted.

Expert from Word to the Wise shares the method of using IP address ranges to attempt to identify an email marketing service and then use tools to query their use policy.

Expert from Spam Resource explains that doing a reverse DNS lookup on the IP address can sometimes reveal the hostname associated with it, which can provide clues about the organization or purpose behind the IP. They caution that not all IPs have helpful rDNS records.

Expert from Email Geeks recommends checking DMARC reports for the IPs, asking internally who is using Oracle to send mail, and talking to tech teams for DKIM selectors and key requisition information.

Expert from Email Geeks explains how to find the owner of an IP address using command line tools or a Google search.

Expert from Email Geeks reports seeing random Oracle activity in the specified IP range in their traps but nothing specific from that exact IP address in the last 45 days.

Expert from Email Geeks shares multiple methods to find emails being sent from an IP address, including using SenderScore, Senderbase, and rDNS lookups via Google.

Documentation from DKIM.org details how to identify the signing domain. Checking for the d= tag within the DKIM-Signature header field will display the domain that signed the message.

Documentation from IETF details the purpose of SPF, which is to prevent sender address forgery. The goal of SPF is to enable recipient mail systems to verify that a message purporting to originate from a specific domain was authorized by the domain's administrative management.

Documentation from Google Workspace Admin Help explains that IP addresses within the 'Received:' headers can be used to identify the source of an email. They provide guidelines on how to interpret these headers and identify potential spoofing or forwarding.

Documentation from DMARC.org details the purpose of DMARC, which is to enable email senders and receivers to improve and monitor protection of the email channel. DMARC builds upon SPF and DKIM by adding a reporting function that allows senders and receivers to analyze DMARC results and improve authentication.

Documentation from RFC Editor details the structure of email headers, including 'Received:' fields. It provides the technical specification for how these headers should be formatted and interpreted, which aids in understanding email routing.

Documentation from Microsoft Support shares that examining the 'Received:' headers in an email can reveal the path the email took. They also provide information on using message trace logs to investigate email flow within an organization.