I am reading about how DNS works in general. From the wiki entry of TTL, I understand TTL (Time to Live) occur in the Domain Name System (DNS), where they are set by an authoritative name server for a particular resource record. When a caching (recursive) nameserver queries the authoritative nameserver for a resource record, it will cache that record for the time (in seconds) specified by the TTL.
Now, I needed to use the Linux CLI tools (
dig) to figure out what is the actual TTL set in the authoritative name server and so used my command as below.
dig +trace +nocmd +noall +answer +ttlid a www.stackoverflow.com #I have omitted the root name server output for better readability. www.stackoverflow.com. 300 IN CNAME stackoverflow.com. stackoverflow.com. 300 IN A 188.8.131.52 ;; Received 80 bytes from 184.108.40.206#53(cf-dns02.stackoverflow.com) in 9 ms
As I could see from the A record of
stackoverflow.com., the TTL value in the authoritative name server is 300.
So, does this mean, if I search for
stackoverflow.com after 300 seconds or 5 minutes, the IP address of
stackoverflow.com would be resolved all the way from the