Map subdomains of localhost to ports.
hello.localhost → localhost:1234
db.localhost → localhost:5432
printer.localhost → localhost:9100
This is a direct continuation of Charles' process: https://inclouds.space/localhost-domains
For this to work, we'll need to do two things:
- redirect
*.localhostto127.0.0.1 - have a server on
127.0.0.1that reverse proxies to the right port
This was tested on Ubuntu 22. Your mileage may vary.
NB: You might not actually need this, systemd-resolved might already be doing
the redirecting! See hacker news.
To get dnsmasq to redirect all subdomains (*.localhost) to 127.0.0.1, install
it (via brew or apt) and then configure it as follows:
echo 'port=5353' | sudo tee -a /etc/dnsmasq.conf
echo 'address=/localhost/127.0.0.1' | sudo tee -a /etc/dnsmasq.conf
sudo systemctl restart dnsmasq
NB: we use port 5353 to avoid conflicts with the systemd-resolved
Next, to further avoid conflicts with systemd-resolved add nameserver 127.0.0.1 to the top of /etc/resolv.conf so that dnsmasq becomes the
primary DNS resolver.
Then, we use caddy to direct subdomains to particular ports.
You can do this by writing a Caddyfile by hand. I've written a little bash
script with Claude's help to do this for me. You can add the bash script
localhost to your PATH. In my case, I added the following line to my
.zshrc.
export PATH="$PATH:$HOME/dev/localhost"
Now you can localhost add hello 8000 or localhost remove.
Run a local server!
echo 'hello.localhost!' > index.html
python3 -m http.server 1234
Name the port!
localhost add hello 1234
Now open hello.localhost in your browser!