DNS Server

Stupid simple Domain Name System server.

Features

1. Supports recursive lookups - starting from the root name servers.
2. Caches response to make subsequent queries faster. This way, query latency can be reduced to 0ms.
3. Zero dependencies.

Example usage

Run the server locally on the 4321 port:

$ go run main.go

Open new terminal window and make a DNS query using dig command-line utility:

$ dig @localhost -p 4321 +noedns www.google.com
; <<>> DiG 9.18.26 <<>> @localhost -p 4321 +noedns www.google.com
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 10586
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www.google.com.			IN	A

;; ANSWER SECTION:
www.google.com.		300	IN	A	142.250.203.132

;; Query time: 96 msec
;; SERVER: ::1#4321(localhost) (UDP)
;; WHEN: Mon Jul 15 20:09:17 CEST 2024
;; MSG SIZE  rcvd: 48

Repeat the same query several times and observe lower latency:

$ dig @localhost -p 4321 +noedns www.google.com
...
;; Query time: 67 msec
...


$ dig @localhost -p 4321 +noedns www.google.com
...
;; Query time: 36 msec
...


$ dig @localhost -p 4321 +noedns www.google.com
...
;; Query time: 0 msec
...