What is email forwarding and how does it differ from relaying?
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Email forwarding is what happens when you tell your inbox "send everything I get to this other address too." It's a user-level setting. You set up a forward on Gmail, and now every email lands in Gmail AND in your work Outlook. Or you set up info@company.com to forward to jane@company.com so Jane handles all the inbound.
Relaying is the server-level process of passing mail between mail servers as part of normal delivery. When you send an email from Mailchimp to a subscriber at Yahoo, Mailchimp's server relays that message to Yahoo's server. That's just how email works. Every outbound message goes through at least one relay.
The key difference: forwarding is something YOU configure for YOUR inbox. Relaying is something SERVERS do to deliver mail across the internet. Forwarding is personal routing. Relaying is infrastructure.
Why this matters for deliverability: forwarding can break SPF alignment because the forwarded message arrives at the final inbox with the original sender's domain but the forwarder's IP address. That mismatch can trigger spam filters. (This is why forwarded newsletters sometimes land in spam even though the original sender's reputation is clean.)
Relaying matters because mail servers only relay for authorized users or specific domains. Open relays (servers that relay for anyone) get blocklisted fast because spammers abuse them. Most legitimate mail servers are configured as closed relays, only accepting messages from authenticated users or trusted domains.
Real-world forwarding scenarios: automatic forwards from one email to another (like forwarding your personal Gmail to work email), alias forwards (like forwarding all team@ emails to individual team members), and catch-all forwards (forwarding everything sent to nonexistent addresses at your domain to one inbox). All of these are user-level. None of them are relaying.
And if you're setting up forwarding and worried about SPF failures, check your current setup with our free SPF checker. If you're troubleshooting whether a delivery issue is forwarding-related or relay-related, try our email header analyzer to see the full path the message took.
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