Lets say I forget to update the SOA serial when updating the zonefile. Of course, this means any slaves will not sync to the master because it thinks no change has been done.
The question I have, is, does SOA serial have any effect on ISP caching nameservers?
Eg, lets say a customer at ISP does a request for A www.example.org and get 22.214.171.124 . Then I change the domain to have IP 126.96.36.199, but forgets to update the SOA serial.
When TTL expires, and customer's ISP caching resolver does a new request for www.example.org and sees 188.8.131.52, will it refuse to update the cache and still serve data out of the cache, if the serial is not incremented?