dns lookup

Did you know? For the past fifteen years, I’ve run a simple little website at xnnd.com that provides a set of DNS lookup tools. My goal was to have a simple set of tools to help you troubleshoot DNS issues. You can do things like look up DMARC settings for a domain, try to find the DKIM selector(s) in use for a domain, check a domain’s BIMI record, query the same IP or domain against a bunch of different public DNS servers all at once (helpful to catch intermittent or propagation-related issues), and a few other things. This past weekend I moved XNND from Amazon’s AWS to Google Cloud (partly to save some money, and partly to see if I could do it), and so far it seems to have moved over just fine — but if you see anything amiss, please feel free to let me know!

Let’s compare B2C versus B2B deliverability issues, shall we?In the B2C (business-to-consumer) or DTC (direct-to-consumer) email marketing universe, the number of mailbox providers, while broad, is very heavily concentrated in the US. There are six providers, that when you add up their subscriber reach, they comprise over 90% of almost any typical US B2C email list: Google, Yahoo, Microsoft, Comcast and Apple. Anything beyond the top five is pretty much in the long tail. (That doesn’t mean you ignore deliverability issues for smaller providers, but when you do a cost/benefit analysis of time investment versus reward, it is often clear that fixing an issue with a big provider first will yield more benefit.)In the US B2B (business to business) email universe, things are not as obviously concentrated. There are more providers and it’s not just a set of six controlling just about all of the mailboxes you’ll want to send mail