Can a machine with a single DNS name have multiple addresses? How could it occur?
To answer your question in short, yes it can happen.
DNS, the Domain Name Service, as you would know, is used to help us resolve Fully Qualified Domain Names (FQDN) to IP addresses. There are different versions of DNS systems running all over the Internet, mainly ranging between Windows (which use the Windows DNS server) and Linux/Unix (using BIND DNS services).
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Considering there are some very popular Web sites which serve millions of DNS queries per day e.g., Google.com, Hotmail.com, it is logical that these domain names cannot solely rely on one single DNS server, cause if that fails, the whole domain could become unreachable!
It is, for this reason, a fault-tolerant DNS service is put in place, which shares the DNS queries amongst several different DNS servers. All servers are configured to either randomly provide clients with IP addresses from a specific pool, or -- by using a round robin method -- cycle between the pool of IP addresses. This is what gives a DNS name multiple IP addresses.
This was first published in April 2007