Network & remote access

OpenTraderWorld controls who can reach the app through four network modes. After install it is localhost-only: nothing on your network can connect until you change this.

The supported way to switch modes is in-app: Settings → Network. Saving shows the exact restart command to run on the host (the app can't restart its own containers); the stack is briefly offline while containers recreate.

The four modes

Mode	Reachable by	Protocol	Use when
Localhost only	this machine	HTTP	Default. Safest, nothing on the network can connect.
Local network (LAN)	devices on your network, via the machine's IP	plain HTTP	Quick LAN access; fine for trusted home networks. Browsers may warn or force-upgrade to HTTPS.
LAN + HTTPS	devices on your network, via a real domain	HTTPS, trusted certificate	LAN access without browser warnings. Nothing exposed to the internet.
Public (Web)	anyone, at your domain	HTTPS (Let's Encrypt)	You want access from anywhere and accept public exposure.

LAN + HTTPS (no browser warnings)

Browsers increasingly refuse or warn on plain-HTTP sites. This mode serves the app to every device on your network with a real, publicly trusted certificate: no warnings, nothing installed on client devices, and nothing exposed to the internet. Domain ownership is proven with a DNS record (ACME DNS-01 challenge), not an inbound connection, and the domain resolves to your machine's private LAN IP.

Set it up at install time (./setup.sh, mode 3) or later in Settings → Network → Local network (LAN) + HTTPS:

1. Sign in at duckdns.org (free), add a subdomain (e.g. myotw.duckdns.org) and copy your account token, or use your own domain on Cloudflare with a DNS-edit API token.
2. Enter the domain + token, plus your machine's LAN IP (with DuckDNS the record is pointed at it automatically; on Cloudflare create the A record yourself).
3. Apply with the restart command shown. The first request can take ~30 s while the certificate is issued.

Then open https://myotw.duckdns.org from any device on your network.

Notes

• Issued certificates appear in public Certificate Transparency logs, so the domain name is publicly visible (the app itself stays LAN-only).
• The DNS token is stored in deploy/dns.env: never commit or share that file.
• This mode uses ports 80 + 443 instead of the custom port.

If the domain doesn't resolve on some devices

Some ISP routers/resolvers silently drop DNS answers pointing to a private IP ("DNS rebind protection"). Fixes, best first:

1. Allow the domain in your router/DNS settings.

2. Enable secure DNS (DNS over HTTPS) in the browser. Chrome: Settings → Privacy and security → Security → Use secure DNS → Cloudflare; Firefox: Settings → Privacy → DNS over HTTPS → Max Protection.

3. Hosts-file workaround (per machine, and phones can't do this). Map the domain to the server's LAN IP:

   # macOS / Linux, then flush the cache (macOS only):
   echo "192.168.1.50 myotw.duckdns.org" | sudo tee -a /etc/hosts
   sudo dscacheutil -flushcache && sudo killall -HUP mDNSResponder

   On Windows, edit C:\Windows\System32\drivers\etc\hosts as Administrator, add the same line, then run ipconfig /flushdns. The hosts file always wins over DNS, so remove the line if the server's IP changes.

Public (Web)

Exposes the app on your own domain with automatic HTTPS.

Prerequisites:

1. A domain with a public A / AAAA record pointing at your server's public IP.
2. Inbound TCP 80 and 443 reaching the server: open them in the router/cloud firewall and port-forward if behind NAT. Port 80 is required for the certificate (HTTP-01 challenge) and redirects to HTTPS.

Pick mode 4 in ./setup.sh or switch in Settings → Network. Caddy obtains and auto-renews a Let's Encrypt certificate on the first request (~30 s).

Anyone can reach the login page once this is on

Only enable it after your admin account exists and with a strong password. Keep deploy/.env secret. Switch back to a private mode any time in Settings → Network.

Changing the mode from the CLI

If you picked the wrong mode at install and can't reach the app at all (e.g. chose localhost on a headless server), edit deploy/network.env directly and restart:

cd deploy
# make it reachable on your LAN over plain HTTP (mode 2):
#   OTW_BIND=0.0.0.0     (was 127.0.0.1)
#   OTW_HTTP_PORT=5454   (or your chosen port)
$EDITOR network.env
docker compose --env-file .env --env-file network.env up -d

network.env is secret-free: it holds the bind interface (127.0.0.1 = this machine only, 0.0.0.0 = all interfaces) and ports, interpolated by Compose. LAN + HTTPS needs more than one line (certificate + DNS token), so set that one up from Settings or ./setup.sh mode 3. Once you can open the app, use Settings → Network.