diff --git a/.env.example b/.env.example
index 1388898..9b788e3 100644
--- a/.env.example
+++ b/.env.example
@@ -13,9 +13,8 @@ LOG_LEVEL=info
 # STATIC_DIR=
 
 # ---- Datum gateway (the Umbrel app we're polling) ----
-# Datum's service alias on Umbrel's shared app network. Override if your Umbrel
-# install exposes a different DNS name.
-DATUM_URL=http://datum:21000
+# Datum's admin UI/API is published by Umbrel on the host at port 21000.
+DATUM_URL=http://127.0.0.1:21000
 DATUM_ADMIN_USER=admin
 DATUM_ADMIN_PASSWORD=
 # How often to scrape /clients (ms). Datum updates per-worker hashrate every
diff --git a/README.md b/README.md
index a8a09d7..d3f3655 100644
--- a/README.md
+++ b/README.md
@@ -46,12 +46,11 @@ Allowlist of npubs is set via `NOSTR_ALLOWED_NPUBS`. Anything else is rejected b
    - Repository URL: `https://git.tx1138.com/lfg2025/gashboard`
    - Compose path: `docker-compose.yml`
    - Add env vars (see `.env.example`)
-   - Remove any old `DATUM_URL=http://10.21...` value from the stack env vars.
-     By default the stack uses `http://datum:21000` on Umbrel's
-     `umbrel_main_network`, so Datum can be recreated without changing a stale
-     IP address.
-   - If your Umbrel install exposes Datum under a different DNS name, set
-     `DATUM_URL=http://<datum-dns-name>:21000`.
+   - Remove any old `DATUM_URL=http://10.21...`,
+     `DATUM_URL=http://datum...`, or `DATUM_URL=http://datum_datum_1...` value
+     from the stack env vars.
+   - By default the stack uses host networking and polls Datum through Umbrel's
+     host-published admin port: `DATUM_URL=http://127.0.0.1:21000`.
 
 4. Open the dashboard, log in with one of the allowed npubs, watch your boards lose at hashing in style.
 
diff --git a/apps/api/src/config.ts b/apps/api/src/config.ts
index d006823..66b7ac6 100644
--- a/apps/api/src/config.ts
+++ b/apps/api/src/config.ts
@@ -53,7 +53,7 @@ export const config = {
   corsOrigin: parsed.CORS_ORIGIN,
   staticDir: parsed.STATIC_DIR,
   datum: {
-    url: (parsed.DATUM_URL ?? "http://datum:21000").replace(/\/$/, ""),
+    url: (parsed.DATUM_URL ?? "http://127.0.0.1:21000").replace(/\/$/, ""),
     adminUser: parsed.DATUM_ADMIN_USER,
     adminPassword: parsed.DATUM_ADMIN_PASSWORD,
     pollIntervalMs: parsed.DATUM_POLL_INTERVAL_MS,
diff --git a/docker-compose.yml b/docker-compose.yml
index 949edad..d3679a8 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -1,7 +1,7 @@
 # gashboard — deploy as a Portainer Stack on the same Umbrel host that runs Datum.
 #
-# Joins Umbrel's shared Docker network so the API can reach Datum through
-# Docker DNS instead of a changing container IP.
+# Uses host networking so the API can reach Datum through the port Umbrel
+# already publishes on the host, avoiding container DNS and changing IPs.
 
 services:
   gashboard:
@@ -21,9 +21,8 @@ services:
       PORT: "1337"
       LOG_LEVEL: "${LOG_LEVEL:-info}"
       CORS_ORIGIN: "${CORS_ORIGIN:-}"
-      # Datum's service alias on Umbrel's shared app network. Override this if
-      # your Umbrel install exposes a different DNS name.
-      DATUM_URL: "${DATUM_URL:-http://datum:21000}"
+      # Datum's admin UI/API is published by Umbrel on the host at port 21000.
+      DATUM_URL: "${DATUM_URL:-http://127.0.0.1:21000}"
       DATUM_ADMIN_USER: "${DATUM_ADMIN_USER:-admin}"
       DATUM_ADMIN_PASSWORD: "${DATUM_ADMIN_PASSWORD?must be set}"
       DATUM_POLL_INTERVAL_MS: "${DATUM_POLL_INTERVAL_MS:-5000}"
@@ -31,17 +30,10 @@ services:
       NOSTR_ALLOWED_NPUBS: "${NOSTR_ALLOWED_NPUBS?must be set}"
       JWT_SECRET: "${JWT_SECRET?must be set}"
       JWT_TTL_SECONDS: "${JWT_TTL_SECONDS:-86400}"
-    ports:
-      - "${PORT:-1337}:1337"
-    networks:
-      - umbrel_main_network
+    network_mode: host
     healthcheck:
       test: ["CMD", "wget", "-qO-", "http://127.0.0.1:1337/healthz"]
       interval: 30s
       timeout: 5s
       retries: 3
       start_period: 15s
-
-networks:
-  umbrel_main_network:
-    external: true