This repository was created to explore email validation with Python. It uses pywin32 to read emails and their headers from the Outlook desktop client on Windows. It then analyzes the values of the headers to verify the emails against SPF and DKIM protocols.
Still a work in progress.
Sample output as of 10/4/2022 when run against an email I received from a Smashing Magazine Newsletter subscription. The DKIM failure is actually what I would expect since it looks like a mailing list is used for this, and this problem is actually one of the driving reasons behind the creation of the Authenticated Received Chain (ARC) protocol published in 2019.
[{'received_from': 'BYAPR04MB6150.namprd04.prod.outlook.com', 'received_by': 'BYAPR04MB5750.namprd04.prod.outlook.com'}, {'received_from': 'DM6PR06CA0045.namprd06.prod.outlook.com', 'received_by': 'BYAPR04MB6150.namprd04.prod.outlook.com'}, {'received_from': 'DM6NAM11FT047.eop-nam11.prod.protection.outlook.com', 'received_by': 'DM6PR06CA0045.outlook.office365.com'}, {'received_from': 'mail212.sea81.mcsv.net', 'received_by': 'DM6NAM11FT047.mail.protection.outlook.com'}]
Total mailservers involved: 5
Obtaining Authorized Senders for Return-Path domain mail212.sea81.mcsv.net...
Obtaining SPF DNS TXT record for domain mail212.sea81.mcsv.net
Getting a list of all authorized senders for domain mail212.sea81.mcsv.net
SPF policy for mail212.sea81.mcsv.net includes SPF policy from spf.mandrillapp.com; recursing...
Obtaining SPF DNS TXT record for domain spf.mandrillapp.com
Getting a list of all authorized senders for domain mail212.sea81.mcsv.net
The following addresses are authorized senders for mail212.sea81.mcsv.net:
148.105.14.212
198.2.128.0/24
198.2.132.0/22
198.2.136.0/23
198.2.145.0/24
198.2.186.0/23
205.201.131.128/25
205.201.134.128/25
205.201.136.0/23
205.201.139.0/24
198.2.177.0/24
198.2.178.0/23
198.2.180.0/24
Checking SPF...
SPF result recorded with Received-SPF header: Pass
SPF=Pass
Checking DKIM...
DKIM Signature: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;d=smashingmagazine.com; s=k1; t=1646838291;i=newsletter@smashingmagazine.com;bh=t3u1lX26nPRNYACI6VjIsaUTMgcHPedvNnTZIYZ7Nug=;h=Subject:From:Reply-To:To:Date:Message-ID:List-ID:List-Unsubscribe: List-Unsubscribe-Post:Content-Type:MIME-Version:CC:Date:Subject;b=eip3LtZ8NYi/F1SX2T5OkOTVIANusWI7jyUo/eH/Aq0XudKaQdmyuBl03IrYPvpVj rlftQxfgOAWN62qYIoGUXLoPwKgeYvK5ptS9SyslyeQeG/i10QomMmoC09zYK7WZcJ U5M9x0zqjGl8S0nKUo7OUeryQD99ON9pyA22PkUk=
Selector = k1
Domain = smashingmagazine.com
Verification Body Hash VW5Zr1z9DOxrUiC8NTwOQ0MbdnETkMQUAAuZvGUREHM= NOT EQUAL to signed body hash t3u1lX26nPRNYACI6VjIsaUTMgcHPedvNnTZIYZ7Nug=; possibly due to mailing list processing
DKIM verification failed