diff --git a/tests/stream_netns/probe.py b/tests/stream_netns/probe.py
index 55bf6e86..dff95a8e 100644
--- a/tests/stream_netns/probe.py
+++ b/tests/stream_netns/probe.py
@@ -103,7 +103,8 @@ class Probes:
         for gateway in NATS:
             for node in (n for n in NODES if n.nat == gateway.name):
                 a, b, c = public["a"], public["b"], public["c"]
-                before = self.exchange(c.name, gateway.ip, node.mapped_port, count=1, timeout=0.35)
+                outsider = next(n for n in NODES if n.country == "c" and not n.nat and n.name != c.name)
+                before = self.exchange(outsider.name, gateway.ip, node.mapped_port, count=1, timeout=0.35)
                 if before["observed"]:
                     raise RuntimeError(f"NAT {node.name}: incoming mapping exists before outbound traffic")
                 first = self.exchange(node.name, a.ip)
diff --git a/tests/stream_netns/run.py b/tests/stream_netns/run.py
index f2e68a62..aa263dbd 100644
--- a/tests/stream_netns/run.py
+++ b/tests/stream_netns/run.py
@@ -24,6 +24,16 @@ def host_snapshot():
     return result
 
 
+def stable_snapshot(value):
+    # DHCP lifetime и route cache age меняются от часов, без изменения конфигурации.
+    if isinstance(value, dict):
+        return {key: stable_snapshot(item) for key, item in value.items()
+                if key not in {"valid_life_time", "preferred_life_time", "expires", "used", "lastuse"}}
+    if isinstance(value, list):
+        return [stable_snapshot(item) for item in value]
+    return value
+
+
 def inside(args):
     def interrupted(signum, _frame):
         raise KeyboardInterrupt(f"signal {signum}")
@@ -97,7 +107,7 @@ def main():
             status = child.wait()
     after = host_snapshot()
     (directory / "host-after.json").write_text(json.dumps(after, indent=2) + "\n")
-    unchanged = before == after and os.readlink("/proc/self/ns/net") == original_namespace
+    unchanged = stable_snapshot(before) == stable_snapshot(after) and os.readlink("/proc/self/ns/net") == original_namespace
     (directory / "host-check.json").write_text(json.dumps({"unchanged": unchanged}, indent=2) + "\n")
     if not unchanged:
         print("FAIL: main network namespace snapshot changed during the run", file=sys.stderr)