Email headers contain a wealth of information about the journey an email takes from the sender to the recipient. One of the most important, yet often overlooked, parts of an email header is the X-Received
field. This field can provide valuable insights into the email’s path through various servers, which can be crucial in troubleshooting delivery issues or investigating suspicious emails.
What is the X-Received Field?
The X-Received
field is a trace field added by each server that processes an email. It records the server’s IP address, the ID assigned to the email by the server, and the exact date and time the server processed the email.
Let’s break down an example:
X-Received: by 2002:a2e:9c09:0:b0:2cd:449:149 with SMTP id s9-20020a2e9c09000000b002cd04490149mr3332612lji.80.1705410410754;
Tue, 16 Jan 2024 05:06:50 -0800 (PST)
Decoding the X-Received Field
- by 2002:a2e:9c09:0:b0:2cd:449:149: This is the IP address of the server that processed the email. It’s in IPv6 format, but it could also be in IPv4 format depending on the server’s configuration.
- with SMTP id s9-20020a2e9c09000000b002cd04490149mr3332612lji.80.1705410410754: This is the unique identifier assigned to the email by the server. It’s typically a long, alphanumeric string that’s unique for each email processed by the server.
- Tue, 16 Jan 2024 05:06:50 -0800 (PST): This is the date and time the server processed the email. It’s in the format “Day, Date Month Year Hour:Minute:Second Timezone (Timezone Abbreviation)”.
Why is the X-Received Field Important?
The X-Received
field is a crucial part of email forensics. It can help identify the path an email took to reach the recipient, which can be useful in identifying bottlenecks or delays in email delivery. It can also help identify the source of an email, which can be useful in investigating phishing or spam emails.
In conclusion, while the X-Received
field might seem like a jumble of numbers and letters at first glance, it holds valuable information about the journey of an email. Understanding this field can provide valuable insights into your email infrastructure and help you troubleshoot delivery issues or investigate suspicious emails.
FAQs:
What do you mean by multiple X-Received in email header?
Multiple X-Received
entries in an email header represent the different servers or nodes that an email has passed through on its journey from the sender to the recipient. Each time an email is received and processed by a server, that server adds its own X-Received
entry to the email header.
This entry includes the server’s IP address, a unique identifier for the email, and the timestamp of when the email was processed. The entries are added in reverse chronological order, meaning the most recent server (usually the recipient’s email server) is at the top, and the original sending server is at the bottom.
By examining these multiple X-Received
entries, you can trace the path the email took across the internet. This can be useful for troubleshooting email delivery issues, investigating potential email spoofing or phishing attempts, and understanding the overall flow of email traffic.
How X-Received Field can identify the path an email took to reach the recipient?
The X-Received
field in an email header is a trace field that records the path an email took as it was relayed from the sender to the recipient. Each time an email passes through a mail server, that server adds an X-Received
field to the header of the email.
Let’s break down your example:
X-Received: by 2002:a50:ee13:0:b0:558:d5ce:dd74 with SMTP id g19-20020a50ee13000000b00558d5cedd74mr3217157eds.34.1705410410051; Tue, 16 Jan 2024 05:06:50 -0800 (PST)
X-Received: by 2002:a2e:9c09:0:b0:2cd:449:149 with SMTP id s9-20020a2e9c09000000b002cd04490149mr3332612lji.80.1705410410754;
Tue, 16 Jan 2024 05:06:50 -0800 (PST)
In this example, there are two X-Received
fields, indicating that the email passed through two servers.
The first X-Received
field (at the bottom) was added by the server with the IP address 2002:a2e:9c09:0:b0:2cd:449:149
. This is likely the server that initially sent the email or an early hop in the email’s journey.
The second X-Received
field (at the top) was added by the server with the IP address 2002:a50:ee13:0:b0:558:d5ce:dd74
. This server received the email from the previous server and processed it next.
By examining these X-Received
fields from bottom to top, you can trace the path the email took from the sender to the recipient. This can be useful for diagnosing delivery issues, identifying the source of spam or phishing emails, and understanding the overall flow of email traffic.
How does tracing the path of an email using the X-Received
field assist in identifying the causes of email delivery delays?
The X-Received
field in an email header can be instrumental in identifying delays in email delivery. Each X-Received
entry includes a timestamp indicating when the corresponding server processed the email. By comparing these timestamps, you can identify where potential delays occurred.
Here’s how it works:
- Identify the servers: Each
X-Received
entry includes the IP address of the server that processed the email. By tracing these servers from the sender to the recipient, you can map out the path the email took. - Compare the timestamps: Each
X-Received
entry also includes a timestamp indicating when the server processed the email. By comparing these timestamps, you can see how long the email spent at each server. - Identify the delays: If there’s a significant time difference between when one server received the email and when the next server processed it, this could indicate a delay. The server that took a longer time to process the email could be experiencing issues, such as high traffic, server downtime, or other technical problems.
By identifying where these delays occur, you can take steps to address them. For example, if a particular server is consistently causing delays, you might choose to route your emails differently, or if the server is within your control, investigate for potential issues causing the delay.
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