This is a tiny experiment to write a C program to run on Heroku. It'll read your IP address from the X-Forwarded-For header and return it as JSON.

You can test this program at ipconfig.herokuapp.com:

curl http://ipconfig.herokuapp.com/

I summarized my experiences in a blog post.

Known problems

Name: JanAhrens/ipconfig-http-server
Brand: JanAhrens/ipconfig-http-server
SKU: project/JanAhrens/ipconfig-http-server
Rating: 4.42 (6 reviews)

Heroku does not filter values for the X-Forwarded-For header: curl -s http://ipconfig.herokuapp.com/ -H 'X-Forwarded-For: ", "attack": true, "foo": "bar' (see #1).

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Ipconfig Http Server

Known problems