Why does a redirect from a local IP address assume localhost?

Question

I am developing a web application on my desktop and it is running on port 80. I am able to access the application from my laptop connected to the LAN by entering my desktop's LAN IP address 192.168.1.8. Now, my application sends a redirect after login, but my laptop assumes the final address is localhost/login. If I manually type in the IP address and URI for any page, it shows that I am logged in, so it works as expected. So, why does the redirect assume localhost?

Both of my machines are linux-based. The laptop being Chrome OS. I am running nginx which proxies non-static file requests to jetty on port 8080.

$ cat /etc/hosts
127.0.0.1 locahost
192.168.1.8 desktop
$ hostname
desktop

The redirect is sent from Jetty, with a HttpServletResponse.sendRedirect()

TL;DR:

Laptop: Request http://192.168.1.8/login
Desktop: Respond with redirect to /index
Laptop: Redirect request to http://localhost/index

Requesting http://desktop/login doesn't work.

Answer 1

There is... nothing anywhere that implicitly redirects to localhost. Something within the framework or application is explicitly doing it.

Answer 2

When connecting to any local interface address, the connection is done from 127.0.0.1 (the local loopback address). This doesn't require a redirect. The name of this address is localhost, as you will find in /etc/hosts. Many applications will check other local interfaces for a name and use that in preference to localhost.

Answer 3

Jetty is prefacing every relative URL with its root domain (in Apache, it's called "Server Name", don't know about Jetty), I suppose: Hence the "localhost". So you need to replace the "localhost" with something that makes sense for both computerss:

You could make a domain like "example.com" your webroot in Jetty and define it as your webroot and add it to the laptop's hosts file.