As BIMI records are accepted by Yahoo! (and other Verizon Media services), Fastmail, and now Gmail, other mailbox providers may be interested in adding support for BIMI. In an effort to support their effort, open source milter-based tools have been made available for common mail platforms (e.g. Postfix).
Below are some tools that you may want to consider when building out your BIMI implementation. As always, you’ll want to carefully evaluate any free and open source software before incorporating it, but these should help provide a clear path forward.
Core BIMI Toolkit
This Mail::BIMI Perl module represents the core library for BIMI, including some useful command line validation tools. It can be used for retrieving, parsing, and validating BIMI Assertion Records, BIMI Indicators, and BIMI VMC Evidence Documents.
Full Authentication Milter (now with BIMI support)
This package is a full Perl implementation of common email authentication standards rolled up into a single easy to use milter. It includes the ability to call the Mail::BIMI module.
This milter goes well beyond BIMI and verifies the following standards:
- Check HELO matches it’s IP address
- DKIM (including ADSP)
- SenderID (why? … don’t ask)
BIMI Validator Web Frontend
The Mail::BIMI module can also be used to support a web-based frontend for validating BIMI records. And while BIMI implementations differ across different mailbox providers (such that not all records that pass BIMI validation will be displayed), this validator follows the most current BIMI specification.