
Exchange Online Mailflow
SPF, DKIM, and DMARC configured correctly. Spoofed sender protection active. Your mail authenticates cleanly, so receiving systems stop treating it as suspect.
Your Domain Is the One Everyone Spoofs
Without correct email authentication, attackers send messages that claim to come from your domain. Receiving mail systems cannot verify your legitimate messages. You have no reporting and no enforcement. The result: your customers get fake invoices from “your” CFO, and your legitimate emails land in Gmail's spam folder because the authentication check fails.
This is not a failure of your IT team. Email authentication works only when SPF, DKIM, and DMARC are deployed together, tuned to your real sending landscape, and rolled out in stages. Microsoft filters spoofed mail out of the box, but it cannot speak for your domains: no Microsoft 365 domain gets a DMARC record automatically, and your custom domains stay unsigned until someone publishes the DKIM keys. That is the gap attackers use — and every marketing tool, CRM, or ERP that sends email on your behalf widens it.
Traditional consulting for email authentication? Five figures. The consultant updates DNS, writes a doc, leaves. Three months later, a new subsidiary sends from a different provider and the setup breaks. Nobody notices until Gmail starts quarantining.
ACTIVITIES IN DETAIL
DELIVERABLES
Sender Inventory: Every sending domain and system, from CRM and ERP to printers and relays
Mail Path: Inbound and outbound connectors, third-party gateways, and header-rewriting rules
Email Authentication: SPF consolidated inside the 10-lookup limit, DKIM signing, DMARC published
DMARC Rollout: Monitoring to quarantine to reject, each step gated on its own evidence
Aggregate Reporting: Reports set up and your team shown how to read them
Forwarding and Rules: External auto-forwarding shut on three levels, transport rules audited
Next steps after Exchange Online Mailflow
A cleanly configured tenant is the foundation. These blueprints build directly on it




