What’s unique about corporate domains vs consumer ISPs?
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Sending to corporate email is a completely different game from sending to Gmail or Outlook personal accounts. Corporate networks add security layers that consumer ISPs don't have.
Most large companies route email through third-party security gateways before it hits their internal servers. You'll see Proofpoint, Mimecast, and Barracuda (among others) sitting in front of Google Workspace or Microsoft Exchange, scanning everything. Corporate admins configure these gateways aggressively for security, which means stricter rules, more aggressive filtering, and quarantine workflows where messages get held for admin review instead of going straight to the user.
So What does this mean for you as a sender? Your email might pass the consumer filters at Gmail, but get caught by a corporate gateway. Organizations also layer on custom blocking rules (like "block anything from non-whitelisted domains") and compliance requirements (finance companies block certain content types, healthcare enforces HIPAA rules). This isn't about your reputation. It's about what the administrator configured for their organization.
B2B senders face a fundamentally different deliverability challenge than B2C senders because you're not just competing with spam filters. You're competing with corporate security policies. The good news: most of these gateways are transparent about what they scan for. Authentication matters more in this environment because it's one of the few things a corporate admin trusts.
Next step: If you send to corporate accounts, test your email through a corporate gateway using a tool like GlockApps that simulates gateway filtering. Make sure your SPF, DKIM, and DMARC are locked down tight.
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