Yes, exactly!

Edit: ...actually, almost! You don't even need Traefik, but this actually doesn't handle ports for you. You'll still need to visit sonarr.local:port. If you want to get rid of the ports, you'll need to set up Traefik or another reverse proxy - see the compose_example.yaml in the repo for a simple example.

If your containers are already available at server_ip:port, on your local network, whether directly or by another proxy, you can just add the label (traefik.http.routers.x.rule=Host(`example.local`)) to the container and this will pick it up, no Traefik needed. (And then visit example.local, or example.local:port if not 80.)

I'm meaning to rework the README a bit to make this clear, and perhaps add a simpler label you can use :)

Edit 2: Reworked the README a bit and added support for a quack_domains.hosts label so you don't have to write out all that Traefik stuff if you don't want :) But to access multiple services without a port, you'll still need to set up a reverse proxy like Traefik, or nginx, or Caddy.

This project uses mDNS, which is specific to the .local TLD. The whole reason that people are against the use of .local is because it would break mDNS. So you can set a custom TLD, but it doesn't matter because this is actually the correct context for .local to be used, and changing the TLD will actually break things for a lot of clients.

I've switched over to using a publicly resolvable domain name, but with a lan prefix (e.g. lan.mystuff.dev) so that I can do DNS challenge let's encrypt certs.

Paired with PowerDNS that acts as an authority for the lan.mystuff.dev domain, I can go to a legit certificate/SSL protected https://sonarr.lan.mystuff.dev url. If I wanted to, I could add cloudflare records for the same services exposed through my router (Like for vpn.lan.mystuff.dev) so that both internal and external resolution is possible.

If you prefer, I think Avahi is able to publish other TLDs, but I played around with it just now and couldn't get it to work. If you have any luck, let me know what worked for you and I'll try to add support :)

This is what I tried, but it fails with Failed to add address: Not supported:

# Set domain-name=lan and enable-wide-area=no
nano /etc/avahi/avahi-daemon.conf
sudo avahi-daemon --reload
sudo avahi-publish-address -R example.lan 192.168.1.123