Blocked from my own sites..............home only............

Coincidentally I was called yesterday by a friend whose web site was "no longer working". The site is hosted on (shudders) Google's Blogger platform and the domain is hosted at (shudders) 1& During an unrelated support call it seems a 1&1 tech support rep, apparition or sentient computer with a mean streak altered the domain name's DNS entries and removed the TXT files that Google referenced to ensure domain ownership, and for good measure the A and CNAME entries that told the world where the domain and the www. subdomain were supposed to go. It took me about 90 seconds to fix and about 45 minutes for the new DNS information to propagate to our neck of the woods.

During that 45 minutes I am certain that the correct DNS information would have been available to others earlier, and some later, as the information cascaded its way to the myriad DNS servers around the world.
Sign up for Cloud Flare CDN (free), you won't have to worry about local servers going down.
Sign up for Cloud Flare CDN (free), you won't have to worry about local servers going down.

Cloudflare is a no-brainer; their free tier is the most comprehensive and generous of just about any freemium service I've ever seen. If your site is static then there is simply no point to doing anything other than hosting the code on GitHub and proxying through Cloudflare: They work seamlessly together.
Even if your domain & all set up properly and its IP didn't change... this symptom can have a different root cause:
I've seen a similar problem with ISPs blocking or blacklisting some IP addresses. This can happen with web, and/or with email.
If it's a web site, you can use this site (there are others too) to see if it's down for everyone, or just for you:
Your hosting provider should monitor this and stay on top of it. But many of them don't. They leave it up to you to find out and report it yourself.
Comcast has this site to report blocked sites and request them to be white-listed:
My provider (Arvixe) has been so bad about this, I'm switching everything to a different provider.
It's been 100 years since I was a DNS admin. If we knew a change was coming, we would begin to advertise shorter cache intervals. I.E. 24 hours out, we might change the cache value from 24 hours to 1 hour, or 15 minutes.

The DNS admin sets the cache value, and anticipated changes means the administrator can shorten the "use by" date of the records it shares about domains it serves.

But it's been a while since I've done this, so perhaps newer DNS servers can advise other servers that have cached the value to update.

But I come from the "good old days" where we used named as a DNS server. I have no clue what is used today, so take this for what it is, history.
I’ve literally never heard of someone being a “DNS admin”… how long ago was this? Was that really a job title?