Looking for rationale against replacing Mailman with native Exchange / 0ffice 365
I've been tasked to replace an existing Mailman implementation with native Office 365 distribution lists. We are aware that individual external contacts will need to be created (and hidden from the GAL), but I'm concerned about how to correctly handle DL-style functionality in our exchange environment.
What should I consider when replacing Mailman functionality with Microsoft Exchange?
- Can the 3rd parties (the contacts in the GAL) negatively impact our MX record's reputation when they send to the distribution list?
- To solve the above issue, should I have a distinct DKIM/DMARC scope for listserv messages?
- Should the DLs with external contact have a different DNS domain? (lists.domain.com)
- What special considerations should I have for bounces, NDRs, and MTA delays?
- Are there any known regulations that a listserv-style archive remedies? (HIPAA)
- Are there any known scalability or performance issues with using O365 instead of Mailman?
What other things should be considered when management wants us to replace mailman with O365?