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MyIP License Build Status Report card

by Andrew Brampton (

(A better) What's My IP Address web application. Determines both your IPv4 and IPv6 addresses, issues WHOIS and reverse DNS lookups, and shows all your HTTP headers.

Check it in action: or read about it on my blog. screenshot

This project was quite literally hacked out in one weekend, and was my first App Engine project.



  • Google Cloud SDK

  • AppEngine Go SDK

    $ gcloud components install app-engine-go
  • Make (which comes on Linux or Mac)

  • npm

Then run

make install-tools


As designed, this Go application will run on the Standard Google App Engine. It requires two to three host names. One that is IPv4 only, and one that is IPv6 only. In my configuration I have that has both A and AAAA records, that has only A records, and that only has AAAA records. These all point to the same App Engine instance.

$ dig		300	IN	A		300	IN	AAAA	2001:4860:4802:32::15

$ dig		300	IN	A

$ dig AAAA		300	IN	AAAA	2001:4860:4802:32::15

All three domain names should be configured in main.go (find the prodConfig var).

To deploy:

make deploy # to prod
make stage  # to stage


To run locally we use the addresses, localhost:8080,, and http://[::1]:8080. The first can be either, and the latter are IPv4 and IPv6 respectively.

To start up a local instance, just execute:

make serve

To test:

make test


To keep libraries up to date run:

make veryclean
make test


  • Add rate limiting of requests
  • Add caching of DNS and WHOIS records (including the iana IP ranges)
  • Add configuration file, so can be hosted on different domains
  • Add a favicon.ico
  • Add Make test (which checks with different build tags, e.g macos,appengine linux,appengine)
  • Implement a App Engine Flex, and other PaaS environments
  • Minify all css and js and combine into one file
  • Do better at determining the root cause errors. e.g If both IPv4/IPv6 fail, then perhaps problem with the site. If IPv6 fails after 30 seconds, perhaps problem with IPv6 connectivity.
  • Refactor the app. We don't need to seperate appengine and not appengine anymore. The code is almost identical.

Licence (Apache 2)

This is not an official Google product (experimental or otherwise), it is just code that happens to be owned by Google.

Copyright 2017,2020 Google Inc. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
See the License for the specific language governing permissions and
limitations under the License.