Is it correct that there is no limit to how many DNS A records can be set on a domain?
My boss asked me this and it made me curious, I can't find anything online.
Registrars and DNS servers for DNS management use a zone file which keeps all your DNS records for things such as A and AAAA records. Zone files are naturally unrestricted in the amount of information they can hold.
Some registrars have limits within their standard DNS management and require users to upgrade to a premium/pro DNS manager which has many more features and increases the limits. I have seen some DNS managers having hidden limits and not something they advertise. So you may need to ask your current registrar for that limit... if one applies.
Your boss has nothing to worry about and he'll be able to have 100's 1000's... and even more... just check with your registrar the limit and upgrade if required.
A record or Address record is a resource record that is used to point to a domain name or a sub-domain to an IP address.
These records(A,AAAA for IPv6, MX e.t.c) are present in the zone file.
There is a limit on the number of nameservers that can be assigned to a domain name.
A domain name can point to multiple IP addresses. You can have unlimited number of IP address or A records for your domain name or sub-domains.
The dns query in this case will be served in a round-robin fashion.