https://github.com/linsomniac/dkim_test

A test/diagnostic program for DKIM messages.
https://github.com/linsomniac/dkim_test

Last synced: 11 days ago
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A test/diagnostic program for DKIM messages.

• Host: GitHub
• URL: https://github.com/linsomniac/dkim_test
• Owner: linsomniac
• License: cc0-1.0
• Created: 2024-01-18T09:55:57.000Z (10 months ago)
• Default Branch: main
• Last Pushed: 2024-01-18T14:52:58.000Z (10 months ago)
• Last Synced: 2024-01-19T13:13:00.968Z (10 months ago)
• Language: Python
• Size: 5.86 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# dkim_test - Display diagnostic information about a DKIM message

This is a python program that can take a DKIM message and verify it.  While

verifying, it will display diagnostic information.  In particular, if the

DKIM signature includes the "z" information, it will display any headers

that do not match the signature.

## Using

You will need the "[dkimpy](https://pypi.org/project/dkimpy/)" library: `pip install dkimpy`

(NOTE: This is different from the similarly named "pydkim")

Then just run `python3 dkim_test `

You can optionally include a DKIM DNS record, otherwise it will be looked up in DNS:

`python3 dkim_test --dns-record 'v=DKIM1; ' `

The DNS record can be looked up using: `host -t txt ._domainkey.` but you must remove any

double-quote/space/double-quote separators within it.

## Getting DKIM Header Tests

The OpenDKIM tool includes a "Diagnostics" setting, which when enabled will include a "z" tag in the

DKIM signature.  This tool will use that information to display which header field is causing the

signature failure.

## Example

```shell

[N] sean@seans-laptop ~/p/dkim_test (master)> ./dkim_test --dns-record 'v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA359FxfMhz6Sw0vszgKMFfk+b6xQ7Z60QRCJRLKGNvok49okHeneQUep30RhcKhBrdo5ICzBIQP3Q7a+FKDPuWQ/erCMCqTSLD/pF/eZVTFqSoF46+IXC4k55POeZlC0PwWbJfjeDrZobuqNBTsUlfk0+hJ8GIkAg0MRbVmwequgrWAFoSlDLtV2WP4vzu+V0ZnV8e4ohZGiYv9kHfWeH7KBKp9U2NLckb6iJzvz4v7D/NjcHUJrPNt8WvlUm41lEi9Y92m52kFkuTlWOySvbL/tQHD+e1YusjkcYL9TqzGZjaioPf6bqyfbP0UFOycdoiRvJBikhAR8m8PWOpmhhmwIDAQAB' test

msg

2024-01-18 02:46:15,234 - debug - DEBUG - sig: {b'v': b'1', b'a': b'rsa-sha256', b'c': b'relaxed/simple', b'd': b'stg.example.com', b's': b'2018', b't': b'1705514370', b'bh': b'IV1s4b3EH75xXFDsvkD/BI5CVv9r6J01axQeUQQBjOw=', b'h': b'From:List-Unsubscribe:List-Unsubscribe-Post:Feedback-ID:From', b'z': b'From:=20"[email protected]=20via=20SMTP=20PRO"=20|List-Unsubscribe:=2\r\n\t 0Test=201|List-Unsubscribe-Post:=20Test=202|Feedback-ID:=20Test=20\r\n\t 3', b'b': b'uauvSkatJmthXvzQCF1pA3D66+X+A5ydRxgGqlclvbOMM0CUFBBFcOOq2EywNx4iP\r\n\t iG77b+F3RYVHMGMnBIE7CRRJvEpinxbqkP+KSL8LY7FGi9xyudVjMq2oBTcJFMI/lo\r\n\t VNlXLcRyi6ryCCSLcwky2UyJMNfOomOe8RcyBZaeX8ZLkRkjCco+evAmMzug7SAVnd\r\n\t iwMSgsKGkY97m5Q1cmmDiJWrU7vrTnkGy09FG6k9k/9nWpRcBFIGjJxDGIPfHFgASa\r\n\t kb05HVIdY0rK36cLMEtQ1H2GIxG7fU6Xa/uCCwRZWnaEKGSShxPos82L/Tia8JZ8gw\r\n\t LhX2eD8bnJgtg=='}

2024-01-18 02:46:15,235 - debug - DEBUG - bh: b'IV1s4b3EH75xXFDsvkD/BI5CVv9r6J01axQeUQQBjOw='

2024-01-18 02:46:15,235 - debug - DEBUG - b'DKIM-Signature' valid: False

Verification results: False

DKIM signature header mismatch: From

  Message: "[email protected] via SMTP PRO" 

     DKIM: "[email protected] via SMTP PRO" 

```