Back up after some extensive modifications.
Setting the DNS request timeout to 30 seconds is no longer necessary -
the service instantly responds to queries.
In order to prevent mail delivery issues if the website is having
technical issues the first time a domain is seen by the service, it will
instantly return a response that it is a valid domain (NXDOMAIN) with a
15 minute TTL. It will then queue up testing of this domain in the
background and automatically keep retrying every few minutes if HTTP
contact fails. After 15 minutes of failed HTTP contact, the DNS service
will begin responding with an invalid domain response (127.0.0.1),
exponentially increasing TTLs and time between background checks until
it reaches about 17 hours between checks. The service automatically run
checks in the background for all domains queried within the last 30 days
and instantly responds to DNS queries with the cached result. If a web
server goes down, has technical issues, etc...it will still be reported
as a valid domain for approximately 4 days after the last successful
HTTP contact while being continually being checked in the background, so
temporary issues won't affect mail delivery.
On 3/11/2019 7:18 PM, RW wrote:
It doesn't seem to be working. Is it gone?
$ dig +norecurse @ns1.singulink.com hwvyuprmjpdrws.com.httpcheck.singulink.com
; <<>> DiG 9.11.0-P5 <<>> +norecurse @ns1.singulink.com
hwvyuprmjpdrws.com.httpcheck.singulink.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: FORMERR, id: 57443
;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
...
