OK, I was too clever by half and it bit me. Basically, I have lots of different hosting providers, I’ve used Bluehost, Inmotion, Cloudways and DigitalOcean and I’ve been using A records to point to the individual hoster so I can easily switch. Last month I thought I was clever and just made tongfamily.com a CNAME that points to the appropriate hoster so I didn’t have to keep changing the A record.
This worked fine except for one small bug. About half the DNS Server around the world refused to propagate anything except the CNAME for tongfamily.com and they failed to propagate the MX Mail records, the NS Records and the important SOA (start of authority records).
Google worked fine so nothing broke since many of the people I correspond with are using Gmail, but iCloud mail, Verizon and bunch of others broke. As soon as I turned tongfamily.com to a regular A record it all worked fine!
Debugging DNS propagation issues
The first thing to know is that at the very top sits your registrar and you have to give the DNS servers that it will be your definition of your services. In my case I use Namecheap as a registrar and it points to a Netlify account.
- First check to make sure the name registrar DNS servers exactly match what the DNS hoster gives you. In my case that’s an exact match.
- Now to go DNS Checker and type your A record name in. In my case this was perfect. Then type in NS records and then MX records and I found that only about half the servers and many of the international ones didn’t have either MX or NS records. You will see that SOA records are not passed around at all. Once I made the above change and waited two hours, everything looks good.
- NSLookup.io is something that Paul turned me onto, this does a detailed record of what it finds and it is good for Google, OpenDNS, Authoritative (which means the home DNS server), so that confirmed there is a propagation problem and not a problem with the “big” DNS providers. but when I to Control D “filtered” DNS servers, I see this error “Cannot find SOA records in com” which is pretty bad and I also saw that in some far away servers.
- I checked a cool tool call dns.squish.net that does a detailed trace of finding records, but this worked find on their servers. The Watch Traversal is very informative.
- You can also try
digon your local machine, but I find that starting with the world first and DNS Checker is fastest
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