CODEWITHSUNDEEP
javascriptnode.jsexpress
decho
decho

Reputation: 895

Express req.ip switches between reporting my local machine address as ::ffff:127.0.0.1 and ::1 on a seemingly random basis

So basically the title says it all.

For the past few hours I have been working on a middleware function that relies on cookies for authentication, something very simple like this:

const authRoute = async (req, res, next) => {
    console.log(req.ip);
    // some other logic here
    return next();
};

app.use('/admin/', authRoute, adminRouter);

The thing is, I haven't modified any of my other code such as for example app.set() or even the app.use() itself, I have been working on this middleware function exclusively. I am also storing this req.ip in my database for auth purposes.

Well, to my surprise this very same req.ip object all of a sudden started to result in:

::1

just after an application/server restart for seemingly no reason. Right before that it was reporting back to me:

::ffff:127.0.0.1

I can verify that because I am console logging this and storing the value in a database as well.

enter image description here

For the record, req.connection.remoteAddress is the same, and I don't have any special settings such as trust proxy or anything like that enabled, I haven't reached that stage of development yet.

So I am really scratching my head right now of what might be causing this, so any help or input is appreciated. I can provide further details as well such as my bin/www config if necessary.

I am on a Win7 machine.

Upvotes: 1

Views: 637

Answers (2)

Xaqron
Xaqron

Reputation: 30837

Check the string for leading ::ffff: and remove it then the remaining is IPv4, otherwise (without leading ::ffff:) it is an IPv6.

The reason you are getting different IPs for localhost is sometimes the request is coming as IPv4 (::ffff:127.0.0.1) and sometimes as IPv6 (::1).

Anyway you need to take care of both versions in production.

Upvotes: 1

pkoulianos
pkoulianos

Reputation: 177

You can try to use req.connection.remoteAddress , i have used it many times with success . This answer is crystal clear https://superuser.com/questions/668004/why-is-my-localhost-not-127-0-0-1-but-1-and-what-notation-is-that

Upvotes: 1

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