Use full headers to find delivery delays or a forged email’s true address

An email’s full headers include information about how it was routed and delivered as well as information about the true sender of the email. View the full headers to find out where an email was delayed or who really sent an email with a forged address.

View an email's full header

  1. Open an email.
  2. Click More | select View Full Header.

Use header info to investigate problems

Find the true address in a forged email

Are you getting emails from an email address you blocked? Not sure if an email is really from who it says it is? An email sender can forge false information to make it look like the email came from a different address than it really did, but you can find the true information in the full header.
  1. View the full header as described above.
  2. Compare the bottom From: address to the address in either the Received or Mailfrom field.
    • The real sending email address is in the top-most Received or Mailfrom field.

Image of a mail header showing a forged from address.

Block or filter the true email address

Now that you have the true email address you can block or filter it.

See where an email was delayed

Delivery records in the full headers show when each computer received the message. The first delivery is at the bottom; the newest at the top. If you find a large time gap between delivery records, that shows which computer delayed before sending it to the next computer.

  1. View the full header as described above.
  2. Find one or more lines that say "Received." These are delivery records.
  3. Review these records to identify any delays.

Image of a mail header showing a delivery delay.

Example: "" received the message from "" with a delay of about 1 hour and 15 minutes.

  Find delays the easy way - Use this third-party tool to parse the header. It makes the information a lot easier to read. Note that this isn't a Yahoo tool and we don't offer support for it.

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