Resolve URL to 0.0.0.0/127.0.0.1/localhost

Question

I'd like to use a real URL instead of localhost for local development (so I can make my development environment more similar to production, not have to remember which port is associated with which service, and have valid certs).

I added an A record to my DNS records for my domain (*.myname.example.com -> 0.0.0.0), but I'm getting a "refused to connect" error; do I need to change something on my machine (e.g. I tried adding the same mapping to /etc/hosts)? I similarly tried an A record to 127.0.0.1 and a CNAME to penguin.linux.test (this resolves to 0.0.0.0 on my host, see below for my setup which has this /etc/hosts rule by default).

For more context (i.e. why editing /etc/hosts is insufficient), I can't actually edit /etc/hosts on my machine, only on the VM my code is running in. More specifically, my stack is below.

• ChromeOS host
• Crostini Arch linux container
• Traefik docker container that routes subdomains to the appropriate services

To resolve any ambiguity about the root of the problem being more fundamental, this works perfectly well if I set my DNS rules to an A record that points to my external IP address (when I'm on a network that allows port forwarding, which isn't always the case, another reason I'm trying to use localhost/127.0.0.1/0.0.0.0).

Answer 1

You’re probably mistaking 0.0.0.0 with 127.0.0.1.

127.0.0.1 is a loopback address which localhost usually resolves to (this is set by default in the hosts file). 0.0.0.0 is a non-routable meta address.

Answer 2

Some admin, make their web application resolve to localhost 127.0.0.1 and your computer when making the request could store the information

Example: www.example.com can have the web Admin

     app.example.com 127.0.0.1 in the A record

And your machine would also store the above. Only that the localhost is now your machine rather than app.example.com