Round Robin DNS

admin
26 Jul, 2014

If you are unaware of this term, then it belongs to – the domain pointing to two servers. Why we are discussing this today because I have seen many people on public forums who wish to host their websites on two servers.

Well, to host one domain on two servers you can use the Round Robin DNS method. The concept is pretty simple. Just add an additional “A” record (IP address) in DNS for your domain name which points to another server.

For example, if your website “yourdomain.com” is hosted on two different servers, on one server the domain has the IP address 10.10.10.10 and on another server. the domain users IP address 10.10.10.11, then make sure the nameserver of your domain “yourdomain.com” has two “A” records; one for each IP address (FYI, by default there is only one “A” record, as your site only exists on one IP address by default).

Round Robin DNS technique basically used in load balancing solutions for load distribution or to provide fault-tolerance provisioning multiple hosts. For example, web servers and FTP servers, by managing DNS responses to address requests from Client computers according to a correct statistical model.

In short, Round Robin DNS simply works by replying to DNS requests, not only with a single IP address but also a list of IP addresses of different servers. With each DNS response, the IP address series in the list is permuted.

Usually, basic IP clients try to establish connections with the first address returned from a DNS query. So that on different connection attempts clients would receive service from different servers. Hence distributing the overall load among all the servers in the cluster.

At first glance, it looks simple, but the several problems associated with this technique like the one arising from record caching in the DNS servers or caching of the DNS records for the domain at the client end such as ISP nameserver cache.

Incoming searches related to round robin dns