u/Coriron

Microsoft's tightening the Tenant External Recipient Rate Limit (TERRL) further, starting Sept 14, 2026. This one specifically targets new tenants, trial tenants, and EDU tenants, not existing tenants.

Quick summary:

New tenants get a ramped quota: 10% in the first 31 days, 25% for days 31–60, full quota after that
Trial tenants drop from 5,000 to 500 external recipients/day
EDU tenants (free A1 licenses etc.) get a separate formula that weighs purchased licenses way more heavily than free ones

Wrote up the details and some worked examples on the formula since the EDU math is a bit counterintuitive: https://lazyadmin.nl/office-365/exchange-online-tightens-outbound-limits-for-new-trial-and-edu-tenants/

We have a customer currently with Proofpoint Essentials. With the acquisition of Hornet, and the future migration of all customers over to Hornet, we are exploring options. I had a demo of Hornet and have to say it looks really good. I'd be interested in feedback from the community on this?

One of our customers has been quoted for Barracuda, though, and the pricing massively undercuts Hornet. How is Barracuda?

Things they are considering with them:

Barracuda Email Gateway Defense (Proofpoint Replacement)
Barracuda Impersonation Protection
Barracuda Domain Fraud Protection
Barracuda Incident Response

Additional services we are looking at is DMARC with Hornet (we currently use another tool, so would bring things together), but obviously there is a heap of other things as well that they offer.

What is your experience with these 2 vendors?

New Exchange Online outbound limits for New Tenants - Limitted to 10% first month!

Proofpoint Essentials / Hornet / Barracuda