Round Robin DNS: Simple Load Balancing Using A Records

Round Robin DNS is a basic load-balancing technique that distributes website traffic across multiple servers. By creating multiple 'A' records with the same hostname but different IP addresses, the DNS server cycles through the IPs, sending each new visitor to a different server. It is a highly cost-effective way to improve capacity.

How DNS Rotation Distributes Traffic

Standard DNS maps one hostname to one IP address. Round Robin maps one hostname to multiple IP addresses.

When a visitor requests your domain, the DNS server returns all IP addresses but rotates their order. The first IP in the list typically receives the connection. Next query, different order, different server.

Example configuration:

www.example.com  →  192.0.2.1

www.example.com  →  192.0.2.2

www.example.com  →  192.0.2.3

Each visitor potentially hits a different server. Traffic distributes roughly evenly across your infrastructure, no specialized hardware required.

Why It Matters: Scaling Without Enterprise Costs

Hardware load balancers cost thousands. Cloud load balancers add monthly fees. Round Robin DNS costs nothing beyond existing DNS service.

For websites outgrowing a single server, Round Robin provides immediate relief, double capacity by adding a second server, triple by adding a third. Scale horizontally without architectural overhaul.

This approach works for stateless applications serving identical content from multiple servers.

Decision Framework: Round Robin vs True Load Balancers

Choose Round Robin when:

• Budget is constrained

• All servers are reliably online

• Application is stateless

• You need quick horizontal scaling

Choose true load balancers when:

• High availability is critical

• You need automatic failover

• Sessions must stick to specific servers

• Traffic patterns require intelligent routing

Round Robin is a capacity solution, not a reliability solution.

Implementation Steps

Step 1: Provision Additional Servers Deploy identical application servers with unique IP addresses. Ensure all serve the same content.

Step 2: Access DNS Manager Log into NameSilo, navigate to Domain Manager, and click the blue globe icon 🌎 to open DNS Manager.

Step 3: Add Multiple A Records Create separate A records for the same hostname, each pointing to a different server IP:

• Host: www | Type: A | Value: 192.0.2.1

• Host: www | Type: A | Value: 192.0.2.2

Step 4: Set Consistent TTL Use identical TTL values (3600 seconds minimum) for all records to ensure synchronized caching behavior.

Step 5: Test Distribution Query your domain repeatedly using dig or online DNS tools. Observe IP rotation in responses.

Common Mistakes

Assuming failover exists: This is critical. If one server dies, DNS continues sending traffic to its IP. Visitors hitting the dead server see errors. Round Robin has zero health awareness, it rotates blindly.

Ignoring DNS caching: Clients cache DNS responses. A visitor may hit the same server repeatedly until their cache expires, regardless of rotation. Distribution is approximate, not precise.

Using for stateful applications: Shopping carts, login sessions, and user state break when requests bounce between servers without session sharing.

Mismatched configurations: All servers must serve identical content.

What This Means for You

NameSilo's DNS Manager supports up to 100 DNS records per domain, more than enough for Round Robin configuration. Add, modify, or remove server IPs instantly as your infrastructure scales.

Register your domain and configure Round Robin in minutes.

Frequently Asked Questions

What is Round Robin DNS? 

A load distribution method using multiple A records to rotate traffic.

Is DNS load balancing free? 

Yes. No additional cost beyond DNS hosting.

Does Round Robin check if a server is offline? 

No. Traffic routes to all IPs regardless of health.

How many A records can I have? 

NameSilo supports 100 DNS records per domain; 2-5 servers is typical.

What is DNS caching and how does it affect Round Robin? 

Clients cache responses, potentially directing repeat visits to the same server.

Is Round Robin good for databases? 

No. Use dedicated replication solutions instead.

How do I test if Round Robin is working? 

Run multiple DNS queries and observe rotating IP order.

What is geographic DNS routing? 

Advanced DNS routing users to servers based on location.