Express.js req.ip is returning ::ffff:127.0.0.1

Question

I am currently trying to get the IP of the requested user. The problem is the IP is returning ::ffff:127.0.0.1 instead of 127.0.0.1. I tried using

Answer 1

This seems to be a quirk of ipv6: for ipv4 addresses, ipv6 seems to mix ipv6 notation with ipv4 notation.

In order to get both ipv4 and ipv6 addresses in the simple, unmixed notation, I am using:

var ip = req.headers['x-forwarded-for'] || req.connection.remoteAddress;
if (ip.substr(0, 7) == "::ffff:") {
  ip = ip.substr(7)
}