Q13 Instructions

Stage 1: Load Email Files

1. Navigate to the folder ./spam/ that contains all .eml email files.
2. Loop through all .eml files and read them using the email module.

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Stage 2: Filter for CYFO INC Recipients

For each email:

1. Retrieve the To: address.
2. Check if the address ends with @find the cyfo inc email.
   • If it does, keep the email.

At the end of this stage, you will have a list of emails sent to CYFO INC employees.

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Stage 3: Extract the First Server from Headers

For each CYFO INC email:

1. Collect all Received: headers (there are usually many).
2. Identify the first sending server:
   • The first sending server is found in the last Received: header (email headers are reverse chronological).
   • If the last headers don’t contain IPs (e.g., spam filters), keep popping the last header until you find one with an IPv4 address.

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Stage 4: Extract Public IPs

From the valid Received: header:

1. Use a regex to find all IPv4 addresses (e.g., 192.168.1.1, 34.71.206.167).
2. For each IP:
   • Use ipaddress.ip_address() to validate it.
   • Skip it if it's a private IP (e.g., 10.x.x.x, 192.168.x.x, etc.).
   • If it’s public, add it to a set of unique IPs.

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Stage 5: Display Results

1. Sort the list of unique public IPs.
2. Print the results.