diff --git a/plugins/dashboard_auth/self_hosted/__init__.py b/plugins/dashboard_auth/self_hosted/__init__.py
index ebfa6876021..325c6536d7e 100644
--- a/plugins/dashboard_auth/self_hosted/__init__.py
+++ b/plugins/dashboard_auth/self_hosted/__init__.py
@@ -610,21 +610,17 @@ class SelfHostedOIDCProvider(DashboardAuthProvider):
         """Fast-fail obviously-broken redirect_uris before bouncing to the IDP.
 
         The IDP's own allowlist is authoritative; this just catches the common
-        operator-error case with a clear message. Mirrors the nous provider.
+        operator-error case with a clear message. We allow any ``http://`` host
+        (not just localhost) so self-hosted dashboards reached over plain HTTP —
+        LAN IPs, internal hostnames, reverse proxies that terminate TLS upstream
+        — are not rejected here; the IDP makes the final call on which
+        redirect_uris are permitted. Mirrors the nous provider.
         """
         parsed = urllib.parse.urlparse(redirect_uri)
         if parsed.scheme not in ("https", "http"):
             raise ProviderError(
                 f"redirect_uri must be http(s), got {redirect_uri!r}"
             )
-        if parsed.scheme == "http" and parsed.hostname not in (
-            "localhost",
-            "127.0.0.1",
-        ):
-            raise ProviderError(
-                "redirect_uri may only use http:// for localhost/127.0.0.1, "
-                f"got {redirect_uri!r}"
-            )
         if not parsed.path or not parsed.path.endswith("/auth/callback"):
             raise ProviderError(
                 "redirect_uri path must end with '/auth/callback', "
diff --git a/tests/plugins/dashboard_auth/test_self_hosted_provider.py b/tests/plugins/dashboard_auth/test_self_hosted_provider.py
index d20e6eb1c25..02e4908c296 100644
--- a/tests/plugins/dashboard_auth/test_self_hosted_provider.py
+++ b/tests/plugins/dashboard_auth/test_self_hosted_provider.py
@@ -496,6 +496,16 @@ class TestStartLogin:
         with pytest.raises(ProviderError, match="/auth/callback"):
             provider.start_login(redirect_uri="https://x.example/oauth/cb")
 
+    def test_allows_http_with_arbitrary_host(self, provider):
+        # http:// is permitted for any host now, not just localhost — the
+        # IDP-side allowlist is authoritative on which redirect_uris are
+        # accepted; this client-side fast-fail must not reject self-hosted
+        # dashboards reached over plain HTTP (LAN IPs, internal hostnames,
+        # TLS-terminating reverse proxies). Should not raise.
+        provider.start_login(redirect_uri="http://hermes.example/auth/callback")
+        provider.start_login(redirect_uri="http://192.168.1.50:9119/auth/callback")
+        provider.start_login(redirect_uri="http://my-internal-host/auth/callback")
+
     def test_allows_http_localhost_redirect(self, provider):
         provider.start_login(redirect_uri="http://localhost:8080/auth/callback")
         provider.start_login(redirect_uri="http://127.0.0.1:8080/auth/callback")