Domains, Subdomains & Routing

How to use subdomains to insulate your reputation. This section explains the #1 infrastructure best practice: sending "marketing" mail from and "transactional" mail from . This ensures a 'cargo' problem on one ship doesn't sink your entire fleet.

14 questions in this topic

Why do ESPs recommend using custom sending domains? What is a return-path or bounce domain? What’s the difference between envelope-from and header-from? How many sending domains should I use? Should I use subdomains for different email streams (marketing vs. transactional)? What is a sending subdomain, and why use one? What is a click-tracking and open-tracking domains? How do I manage the reputation of multiple IPs/domains? What is a smart host or relay host? What is mail routing and how does it differ from forwarding? What’s the difference between internal and external routing? How can you test routing paths (traceroute, MX lookup)? What’s the impact of domain age and reputation? How do redirects and shorteners affect domain reputation?

Questions about Domains, Subdomains & Routing