Back to feed
Dev.to
Dev.to
7/24/2026
DNS Round-Robin: The Cheapest Load Balancer Is Three A Records and a Rotating Answer

DNS Round-Robin: The Cheapest Load Balancer Is Three A Records and a Rotating Answer

Short summary

A hands-on Protocol Lab that demonstrates DNS round-robin load balancing using BIND9's rrset-order cyclic setting in a containerlab environment. One hostname holds three A records, and the authoritative server rotates their order on every response so successive clients connect to different backends. The lab covers RRsets, TTL and caching limitations, and trade-offs versus anycast, ECMP, and IPVS, with verification commands and RFC references.

  • •DNS round-robin rotates A record order per response to distribute clients across backends
  • •Lab uses BIND9 with rrset-order cyclic in containerlab, verified with repeated dig queries
  • •Discusses trade-offs: no health checks, caching blunts distribution, compared to anycast/ECMP/IPVS

Generated with AI, which can make mistakes.

Read full article at Dev.to

Is this a good recommendation for you?

Comments

Failed to load comments. Please try again.

Explore more

Split-Horizon DNS: One Name, Two Answers, and the Server Decides by Who's Asking
Dev.to
DNS Caching Explained: Watch TTLs Count Down and NXDOMAIN Get Cached Too
Dev.to
The original title is: "ECMP Explained: Two Equal Paths, and the Kernel Hashes Flows Across Them"
Dev.to
The original title is: "Bind9 vs PowerDNS at Home: Which One to Run When You Actually Need Local DNS"
Dev.to