diff --git a/contrib/testing/README.md b/contrib/testing/README.md
index caa5e19..1015c98 100644
--- a/contrib/testing/README.md
+++ b/contrib/testing/README.md
@@ -60,7 +60,9 @@ one-off files in `/tmp`:
   envelope plus an unsigned, non-SRS internal LMTP message while an
   unreachable global relayhost is enabled. This proves that internal LMTP
   routing takes precedence, after which the test restores the exact SMTP
-  configuration and active service.
+  configuration and active service. The fixture itself is unprivileged; the
+  script uses sudo only for the already-authorized `bongo-admin` and
+  `systemctl` operations.
 - `smtp-client-interoperability-check.py` repeats real delivery with curl,
   swaks, Xeams Email Sender, GNU Mailutils, and paced Telnet input. It covers
   authenticated STARTTLS submission plus unauthenticated local delivery on
diff --git a/contrib/testing/smtp-lmtp-delivery-check.py b/contrib/testing/smtp-lmtp-delivery-check.py
index e4ff357..dfb3b05 100755
--- a/contrib/testing/smtp-lmtp-delivery-check.py
+++ b/contrib/testing/smtp-lmtp-delivery-check.py
@@ -52,6 +52,12 @@ def load_helpers():
 SMTP07 = load_helpers()
 
 
+def privileged(arguments: list[str]) -> list[str]:
+    if os.geteuid() == 0:
+        return arguments
+    return ["/usr/bin/sudo", "-n", *arguments]
+
+
 @dataclass
 class LMTPCapture:
     lock: threading.Lock = field(default_factory=threading.Lock)
@@ -167,7 +173,9 @@ class ThreadingLMTPServer(
 
 
 def read_configuration(name: str) -> dict:
-    completed = SMTP07.run([SMTP07.ADMIN, "__config-read", name])
+    completed = SMTP07.run(
+        privileged([SMTP07.ADMIN, "__config-read", name])
+    )
     try:
         value = json.loads(completed.stdout)
     except json.JSONDecodeError as error:
@@ -181,11 +189,26 @@ def read_configuration(name: str) -> dict:
 
 def replace_configuration(name: str, value: dict) -> None:
     SMTP07.run(
-        [SMTP07.ADMIN, "__config-replace", name],
+        privileged([SMTP07.ADMIN, "__config-replace", name]),
         input_text=json.dumps(value, separators=(",", ":")),
     )
 
 
+def service_active() -> bool:
+    return SMTP07.run(
+        privileged(
+            [SMTP07.SYSTEMCTL, "is-active", "--quiet", "bongo.service"]
+        ),
+        check=False,
+    ).returncode == 0
+
+
+def restart_bongo() -> None:
+    SMTP07.run(
+        privileged([SMTP07.SYSTEMCTL, "restart", "bongo.service"])
+    )
+
+
 def submit(host: str, port: int) -> None:
     message = (
         f"From: Mailman return <{SENDER}>\r\n"
@@ -254,9 +277,7 @@ def validate(delivery: tuple[bytes, bytes, bytes]) -> None:
 
 
 def perform_test() -> None:
-    if os.geteuid() != 0:
-        raise SMTP20Error("the live LMTP test must run as root")
-    originally_active = SMTP07.service_active()
+    originally_active = service_active()
     if not originally_active:
         raise SMTP20Error("bongo.service must be active before this test")
 
@@ -305,7 +326,7 @@ def perform_test() -> None:
     try:
         replace_configuration("smtp", test_smtp)
         configuration_changed = True
-        SMTP07.run([SMTP07.SYSTEMCTL, "restart", "bongo.service"])
+        restart_bongo()
         SMTP07.INTERNAL_HOST = internal_host
         SMTP07.INTERNAL_PORT = internal_port
         SMTP07.wait_for_bongo()
@@ -331,7 +352,7 @@ def perform_test() -> None:
             restoration_errors.append(f"LMTP fixture shutdown failed: {error}")
         if originally_active:
             try:
-                SMTP07.run([SMTP07.SYSTEMCTL, "restart", "bongo.service"])
+                restart_bongo()
                 SMTP07.INTERNAL_HOST = internal_host
                 SMTP07.INTERNAL_PORT = internal_port
                 SMTP07.wait_for_bongo()
diff --git a/docs/release-testing-0.7.md b/docs/release-testing-0.7.md
index 1acb794..4d59a22 100644
--- a/docs/release-testing-0.7.md
+++ b/docs/release-testing-0.7.md
@@ -148,7 +148,7 @@ inputs and outputs is absent from the ZIP.
 | SMTP-26 | IDNA2008 domains use one canonical A-label in config, aliases, DNS lookup, SMTP and Web compose |  |  |  |
 | SMTP-18 | Recipient validation, multiple recipients, partial refusal, aliases |  |  |  |
 | SMTP-19 | Domain/address aliases, forwarding loops, and SRS forwarding |  |  |  |
-| SMTP-20 | Trusted internal SMTP to disposable LMTP preserves the envelope and adds neither DKIM nor SRS |  |  |  |
+| SMTP-20 | Trusted internal SMTP to disposable LMTP preserves the envelope and adds neither DKIM nor SRS | [PASS](test-evidence/0.7-r1.md#smtp-20) |  |  |
 | SMTP-21 | LMTP per-recipient 2xx, 4xx, 5xx, retry, and duplicate prevention |  |  |  |
 | SMTP-22 | XCLIENT/XFORWARD negotiation only to trusted destinations |  |  |  |
 | SMTP-23 | Fallback client-address header only for configured trusted peers |  |  |  |
diff --git a/docs/test-evidence/0.7-r1.md b/docs/test-evidence/0.7-r1.md
index 0fcdde3..3672a97 100644
--- a/docs/test-evidence/0.7-r1.md
+++ b/docs/test-evidence/0.7-r1.md
@@ -2452,22 +2452,46 @@ This models mail returned from Mailman over the trusted internal SMTP
 listener: internal ingress is not signed merely on receipt, but the message
 is signed before it leaves Bongo for an external relay or recipient.
 
-The recovery phase deliberately installs an incorrect relay password,
-verifies that the message remains in Queue 7 and is not accepted by the
-relay, repairs the secret, explicitly retries the retained entry, and
-requires successful signed delivery. Commit `8f0c1518` makes this
-administrative retry reliable by reserving the queue entry before `QRUN`
-acknowledges it; a concurrent attempt is now reported as busy instead of
-silently losing the retry.
+The two recovery phases first select a bound but non-listening loopback port
+and then install an incorrect relay password. In both cases the test verifies
+that the message remains in Queue 7 and is not accepted by the relay. It then
+repairs the endpoint or secret, retries the retained entry, and requires
+successful signed delivery. Commit `8f0c1518` makes this administrative retry
+reliable by reserving the queue entry before `QRUN` acknowledges it; a
+concurrent attempt is now reported as busy instead of silently losing the
+retry.
 
 ```text
-SMTP-09 PASS hostname=localhost ports=12525/12465 starttls=no-auth implicit-tls=auth failure=retained recovery=delivered trusted-port26=dkim-signed dkim=verified queue-clean=yes config-restored=yes
+SMTP-09 PASS hostname=localhost ports=12525/12465 starttls=no-auth implicit-tls=auth unreachable=retained/recovered auth-failure=retained/recovered trusted-port26=dkim-signed dkim=verified queue-clean=yes config-restored=yes
 ```
 
 The test restored the exact SMTP Store document, removed its queue entries,
 password and CA files, and returned `bongo.service` to its original active
 state.
 
+## SMTP-20
+
+Result: **PASS**
+
+The reusable `smtp-lmtp-delivery-check.py` starts a loopback-only,
+status-aware LMTP fixture on an unprivileged port. It adds one temporary
+transport-domain mapping, enables an intentionally unreachable global
+relayhost, and submits a Mailman-style message through trusted port 26.
+
+The installed Bongo client selected the internal LMTP transport before the
+global relayhost, preserved the original envelope sender and recipient, and
+delivered exactly one message. The captured internal copy had neither a
+`DKIM-Signature` nor an SRS envelope. This proves both the internal-delivery
+exception and that enabling a global relayhost cannot redirect LMTP traffic
+outside Bongo.
+
+```text
+SMTP-20 PASS ingress=trusted-internal-smtp transport=lmtp relayhost=bypassed envelope=original dkim=absent srs=absent duplicate=no queue-clean=yes config-restored=yes service-restored=active
+```
+
+The test removed its marked Queue data, stopped the fixture, restored the
+exact SMTP Store document, and returned `bongo.service` to the active state.
+
 ## SMTP-27
 
 Result: **PASS**