diff --git a/tests/integration/1_minute/testnat.nim b/tests/integration/1_minute/testnat.nim
index 50c0467d..4a76e31c 100644
--- a/tests/integration/1_minute/testnat.nim
+++ b/tests/integration/1_minute/testnat.nim
@@ -1,5 +1,6 @@
 import std/json
 import std/options
+import std/sequtils
 import pkg/chronos
 import pkg/questionable/results
 
@@ -7,7 +8,13 @@ import ../multinodes
 import ../storageclient
 import ../storageconfig
 
-multinodesuite "AutoNAT integration":
+const
+  DetectionTimeout = 15_000
+  RelayTimeout = 30_000
+  PollInterval = 1_000
+
+# Reminder: multinodesuite setup the first node as bootstrap node
+multinodesuite "AutoNAT detection":
   let natConfig = NodeConfigs(
     clients: StorageConfigs
       .init(nodes = 2)
@@ -19,14 +26,145 @@ multinodesuite "AutoNAT integration":
       # .withLogLevel("DEBUG")
       .some
   )
-
-  # Reminder: multinodesuite setup the first node as bootstrap node
   test "node is reachable when using bootstrap node on same network", natConfig:
-    let node1 = clients()[0]
     let node2 = clients()[1]
 
     check eventuallySafe(
       (await node2.client.natReachability()).get() == "Reachable",
-      timeout = 30_000,
-      pollInterval = 500,
+      timeout = RelayTimeout,
+      pollInterval = PollInterval,
+    )
+
+    check eventuallySafe(
+      not (await node2.client.natRelayRunning()).get(),
+      timeout = RelayTimeout,
+      pollInterval = PollInterval,
+    )
+
+  let autonatConfig = NodeConfigs(
+    clients: StorageConfigs
+      .init(nodes = 2)
+      .withRelay(idx = 0)
+      .withNatSimulation(idx = 1)
+      .withNatNumPeersToAsk(1)
+      .withNatMinConfidence(0.5)
+      .withNatScheduleInterval(10.seconds)
+      .withNatMaxQueueSize(1)
+      # .withLogLevel("DEBUG")
+      # .debug()
+      # .withLogFile()
+      .some
+  )
+  # node2 is behind simulated NAT: AutoNAT peers try to dial back but are blocked.
+  test "nat node is detected as not reachable and starts relay", autonatConfig:
+    let node2 = clients()[1]
+
+    check eventuallySafe(
+      (await node2.client.natReachability()).get() == "NotReachable",
+      timeout = DetectionTimeout,
+      pollInterval = PollInterval,
+    )
+
+    check eventuallySafe(
+      (await node2.client.natRelayRunning()).get(),
+      timeout = RelayTimeout,
+      pollInterval = PollInterval,
+    )
+
+    check eventuallySafe(
+      block:
+        let addrs = (await node2.client.info()).get["addrs"].getElems.mapIt(it.getStr)
+        addrs.anyIt("p2p-circuit" in it),
+      timeout = RelayTimeout,
+      pollInterval = PollInterval,
+    )
+
+  let transitionConfig = NodeConfigs(
+    clients: StorageConfigs
+      .init(nodes = 2)
+      .withRelay(idx = 0)
+      .withNatSimulation(idx = 1)
+      .withNatNumPeersToAsk(1)
+      .withNatMinConfidence(0.5)
+      .withNatScheduleInterval(5.seconds)
+      .withNatMaxQueueSize(1).some
+  )
+  # node2 starts behind simulated NAT (NotReachable + relay), then NAT is lifted
+  # and AutoNAT detects Reachable on the next scheduled check.
+  test "nat node recovers to reachable when nat is lifted", transitionConfig:
+    let node2 = clients()[1]
+
+    check eventuallySafe(
+      (await node2.client.natReachability()).get() == "NotReachable",
+      timeout = DetectionTimeout,
+      pollInterval = PollInterval,
+    )
+
+    check eventuallySafe(
+      (await node2.client.natRelayRunning()).get(),
+      timeout = RelayTimeout,
+      pollInterval = PollInterval,
+    )
+
+    check eventuallySafe(
+      block:
+        let addrs = (await node2.client.info()).get["addrs"].getElems.mapIt(it.getStr)
+        addrs.anyIt("p2p-circuit" in it),
+      timeout = RelayTimeout,
+      pollInterval = PollInterval,
+    )
+
+    check (await node2.client.setNatFiltering("endpoint-independent")).isOk
+
+    check eventuallySafe(
+      (await node2.client.natReachability()).get() == "Reachable",
+      timeout = RelayTimeout,
+      pollInterval = PollInterval,
+    )
+
+    check eventuallySafe(
+      not (await node2.client.natRelayRunning()).get(),
+      timeout = RelayTimeout,
+      pollInterval = PollInterval,
+    )
+
+  let natToSimConfig = NodeConfigs(
+    clients: StorageConfigs
+      .init(nodes = 2)
+      .withRelay(idx = 0)
+      .withNatSimulation(idx = 1, "endpoint-independent")
+      .withNatNumPeersToAsk(1)
+      .withNatMinConfidence(0.5)
+      .withNatScheduleInterval(5.seconds)
+      .withNatMaxQueueSize(1).some
+  )
+  # node2 starts reachable (endpoint-independent NAT sim = pass-through),
+  # then NAT is tightened to block dial-backs and AutoNAT detects NotReachable.
+  test "reachable node becomes not reachable when nat is applied", natToSimConfig:
+    let node2 = clients()[1]
+
+    check eventuallySafe(
+      (await node2.client.natReachability()).get() == "Reachable",
+      timeout = RelayTimeout,
+      pollInterval = PollInterval,
+    )
+
+    check eventuallySafe(
+      not (await node2.client.natRelayRunning()).get(),
+      timeout = RelayTimeout,
+      pollInterval = PollInterval,
+    )
+
+    check (await node2.client.setNatFiltering("address-and-port-dependent")).isOk
+
+    check eventuallySafe(
+      (await node2.client.natReachability()).get() == "NotReachable",
+      timeout = RelayTimeout,
+      pollInterval = PollInterval,
+    )
+
+    check eventuallySafe(
+      (await node2.client.natRelayRunning()).get(),
+      timeout = RelayTimeout,
+      pollInterval = PollInterval,
     )
diff --git a/tests/integration/storageclient.nim b/tests/integration/storageclient.nim
index 62d72917..2c0ec356 100644
--- a/tests/integration/storageclient.nim
+++ b/tests/integration/storageclient.nim
@@ -281,3 +281,23 @@ proc natReachability*(
     return info.get()["nat"]["reachability"].getStr().success
   except KeyError as e:
     return failure e.msg
+
+proc natRelayRunning*(
+    client: StorageClient
+): Future[?!bool] {.async: (raises: [CancelledError, HttpError]).} =
+  let info = await client.info()
+  if info.isErr:
+    return failure "Failed to get node info"
+  try:
+    return info.get()["nat"]["relayRunning"].getBool().success
+  except KeyError as e:
+    return failure e.msg
+
+proc setNatFiltering*(
+    client: StorageClient, filtering: string
+): Future[?!void] {.async: (raises: [CancelledError, HttpError]).} =
+  let response =
+    await client.post(client.baseurl & "/debug/nat/filtering?filtering=" & filtering)
+  if response.status != 200:
+    return failure "Failed to set NAT filtering: " & $response.status
+  return success()
diff --git a/tests/integration/storageconfig.nim b/tests/integration/storageconfig.nim
index 7b218bd3..ed839b1f 100644
--- a/tests/integration/storageconfig.nim
+++ b/tests/integration/storageconfig.nim
@@ -338,3 +338,35 @@ proc withExtIp*(
   for config in startConfig.configs.mitems:
     config.addCliOption("--nat", "extip:" & ip)
   return startConfig
+
+proc withRelay*(
+    self: StorageConfigs, idx: int
+): StorageConfigs {.raises: [StorageConfigError].} =
+  self.checkBounds idx
+
+  var startConfig = self
+  startConfig.configs[idx].addCliOption("--relay")
+  return startConfig
+
+proc withRelay*(self: StorageConfigs): StorageConfigs {.raises: [StorageConfigError].} =
+  var startConfig = self
+  for config in startConfig.configs.mitems:
+    config.addCliOption("--relay")
+  return startConfig
+
+proc withNatSimulation*(
+    self: StorageConfigs, idx: int, filtering = "address-and-port-dependent"
+): StorageConfigs {.raises: [StorageConfigError].} =
+  self.checkBounds idx
+
+  var startConfig = self
+  startConfig.configs[idx].addCliOption("--nat-simulation", filtering)
+  return startConfig
+
+proc withNatSimulation*(
+    self: StorageConfigs, filtering = "address-and-port-dependent"
+): StorageConfigs {.raises: [StorageConfigError].} =
+  var startConfig = self
+  for config in startConfig.configs.mitems:
+    config.addCliOption("--nat-simulation", filtering)
+  return startConfig