[BUG] useLocalInstall() does not recognize common homelab/internal DNS domains such as .home

[williamscody]

Summary

The useLocalInstall() hook currently only treats the following hostnames as “local installs”:

* localhost
* 127.0.0.1
* ::1
* *.local
* RFC1918 private IP ranges (192.168.x.x, 10.x.x.x, 172.16-31.x.x)

This prevents self-hosted OpenHamClock instances accessed through common internal DNS/reverse proxy setups from being recognized as local installs.

As a result, features gated behind isLocalInstall (such as UDP Spots) are incorrectly disabled even though the application is running entirely on the local LAN.

Current code:

if (host === 'localhost' || host === '127.0.0.1' || host === '::1') return true;
if (host.endsWith('.local')) return true;
if (host.startsWith('10.') || host.startsWith('192.168.')) return true;

Problem

Many modern homelab/self-hosted environments use internal DNS domains such as:

• .home
• .lan
• .internal
• custom split-horizon DNS domains

For example:
https://hamclock.home
is a completely local installation behind:

• local DNS
• local reverse proxy
• local TLS certificates
• LAN-only routing

However, OpenHamClock reports "Hosted mode" and disables local-only functionality (like UDP Spots as the DX Cluster source)

Additional Issue with .local

On macOS/iOS, .local is reserved for Bonjour/mDNS and is often unreliable or inappropriate for manually-defined DNS records.

Many homelab users intentionally avoid .local for this reason and instead use:

• .home
• .lan
• custom internal domains

So limiting local detection to .local creates avoidable interoperability issues.

Suggested Fix

At minimum, support additional common internal domains:

if (
  host.endsWith('.local') ||
  host.endsWith('.home') ||
  host.endsWith('.lan')
) return true;

Better Long-Term Approach

Instead of hardcoding domain suffixes, consider determining “local install” based on:

• whether the backend is self-hosted
• whether the frontend/backend origins match
• whether the server is reachable on RFC1918/private addressing
• an explicit environment variable/config option

Environment

• OpenHamClock latest release (26.3.2)
• Ubuntu 24.04
• Caddy reverse proxy
• AdGuard Home local DNS
• macOS clients