nip.io : An interesting wildcard DNS service

This is a peculiar post about a nice little DNS service I came across few days ago. While reviewing a pull request I came across an address along the lines https://192.168.1.56.nip.io - I couldn't find an immediate clarification and searching I could find the Github repo of the project but I couldn't understand how it worked.

Later our DevOps engineer had to explain to in detail on what this is and how it works !

The nice little utility service has precreated wild card DNS entries for the entire private IP address range. Queries like NOTEXISTING.192.168.2.98.nip.io will get resolved to 192.168.2.168

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bkb@bkb-dev-server1:~/src/discovery$ dig NOTEXISTING.192.168.2.98.nip.io

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; <<>> DiG 9.16.1-Ubuntu <<>> NOTEXISTING.192.168.2.98.nip.io

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12130

;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

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;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags:; udp: 512

;; QUESTION SECTION:

;NOTEXISTING.192.168.2.98.nip.io. IN A

​

;; ANSWER SECTION:

NOTEXISTING.192.168.2.98.nip.io. 86400 IN A 192.168.2.98

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;; Query time: 583 msec

;; SERVER: 208.66.16.191#53(208.66.16.191)

;; WHEN: Mon Nov 27 03:50:17 AST 2023

;; MSG SIZE rcvd: 76

​

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This is a very useful trick if we don't want to edit /etc/hosts or equivalent for tools or software running locally or for scenarios where a DNS record is required.

Learn more https://nip.io

Happy to learn something cool and new !

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