I'm experiencing symptoms similar to those of the other question. That is, peoples are complaining about a domain name being inaccessible. And then, it suddenly starts working after a while. But I doubt it's because of unreliable DNS
servers. They are of my domain name registrar, which is pretty popular in my country.
Could there be some other reasons for this? It's a subdomain, like in sub.example.com
and I make it work with wildcard DNS
record. Could that possibly be a reason? Maybe some old DNS
servers doesn't understand these sort of things? The other reason I can think of is some temporary issues in the internet, like some hosts can't access the other ones? Or some DNS
servers filtering out records by some criterion?
UPD The setup is simple, no load balancers, no clusters, no round-robin DNS
servers. And I'm talking about publicly available server. The users are the users of the internet. I'm managing both example.com
and sub.example.com
. They are in one DNS
zone.
UPD Or maybe after all it's because of the domain registrar. Its servers respond with a timeout:
>nslookup sub.example.com ns.domain.registrar.com
DNS request timed out.
timeout was 2 seconds.
Server: UnKnown
Address: 52.16.198.15
Name: sub.example.com
Address: 51.59.10.10
I suppose, not all the DNS-servers would tolerate timeouts, don't you think?