diff --git a/backend/agent/src/MoShiro.Agent/Dial/ControlBackoff.cs b/backend/agent/src/MoShiro.Agent/Dial/ControlBackoff.cs
index 50e50a5..59257a3 100644
--- a/backend/agent/src/MoShiro.Agent/Dial/ControlBackoff.cs
+++ b/backend/agent/src/MoShiro.Agent/Dial/ControlBackoff.cs
@@ -17,6 +17,8 @@ public sealed class ControlBackoff
         TimeSpan.FromSeconds(32),
     ];
 
+    private const int MaxMinutes = 10;
+
     private int _attempt;
 
     public int Attempts => Volatile.Read(ref _attempt);
@@ -24,7 +26,13 @@ public sealed class ControlBackoff
     public TimeSpan Next()
     {
         int attempt = Interlocked.Increment(ref _attempt) - 1;
-        return attempt < s_delays.Length ? s_delays[attempt] : TimeSpan.FromMinutes(1);
+        if (attempt < s_delays.Length)
+        {
+            return s_delays[attempt];
+        }
+
+        // 表走完还连不上（对端关了、这台机器没有这条路由）：一分钟起继续翻倍，最长十分钟，不再每分钟白白重试一次、写三条日志
+        return TimeSpan.FromMinutes(Math.Min(MaxMinutes, 1 << Math.Min(attempt - s_delays.Length, 4)));
     }
 
     public void Reset() => Interlocked.Exchange(ref _attempt, 0);
diff --git a/backend/agent/src/MoShiro.Agent/Dial/QuicRedialBackoff.cs b/backend/agent/src/MoShiro.Agent/Dial/QuicRedialBackoff.cs
index 995bd1b..cfee13d 100644
--- a/backend/agent/src/MoShiro.Agent/Dial/QuicRedialBackoff.cs
+++ b/backend/agent/src/MoShiro.Agent/Dial/QuicRedialBackoff.cs
@@ -8,6 +8,8 @@ public sealed class QuicRedialBackoff
 {
     private static readonly TimeSpan[] s_delays = [TimeSpan.FromSeconds(1), TimeSpan.FromSeconds(2), TimeSpan.FromSeconds(3), TimeSpan.FromSeconds(5)];
 
+    private const int ShortAttempts = 12;
+
     private int _attempt;
 
     public int Attempts => _attempt;
@@ -15,6 +17,12 @@ public sealed class QuicRedialBackoff
     public TimeSpan Next(Random? random = null)
     {
         TimeSpan delay = s_delays[Math.Min(_attempt, s_delays.Length - 1)];
+        if (_attempt >= ShortAttempts)
+        {
+            // 短间隔已经连续失败了这么多次：这条路径大概率是死的（对端不通、被丢弃），握手和日志都是白费，翻倍退避，最长五分钟
+            delay = TimeSpan.FromSeconds(Math.Min(300, 5 * (1 << Math.Min(_attempt - ShortAttempts + 1, 6))));
+        }
+
         _attempt++;
         return random is null ? delay : delay * (0.8 + (0.4 * random.NextDouble()));
     }
diff --git a/backend/agent/tests/MoShiro.Agent.Tests/ControlBackoffTests.cs b/backend/agent/tests/MoShiro.Agent.Tests/ControlBackoffTests.cs
index c8e639a..c13b4b7 100644
--- a/backend/agent/tests/MoShiro.Agent.Tests/ControlBackoffTests.cs
+++ b/backend/agent/tests/MoShiro.Agent.Tests/ControlBackoffTests.cs
@@ -4,7 +4,7 @@ namespace MoShiro.Agent.Tests;
 public sealed class ControlBackoffTests
 {
     [Fact]
-    public void Next_UsesRequestedEscalationThenCapsAtOneMinute()
+    public void Next_UsesRequestedEscalationThenKeepsDoublingToTenMinutes()
     {
         var backoff = new ControlBackoff();
         TimeSpan[] expected =
@@ -13,7 +13,8 @@ public sealed class ControlBackoffTests
             TimeSpan.FromSeconds(8), TimeSpan.FromSeconds(16),
             TimeSpan.FromSeconds(32), TimeSpan.FromSeconds(32), TimeSpan.FromSeconds(32),
             TimeSpan.FromSeconds(32), TimeSpan.FromSeconds(32),
-            TimeSpan.FromMinutes(1), TimeSpan.FromMinutes(1),
+            TimeSpan.FromMinutes(1), TimeSpan.FromMinutes(2), TimeSpan.FromMinutes(4),
+            TimeSpan.FromMinutes(8), TimeSpan.FromMinutes(10), TimeSpan.FromMinutes(10),
         ];
 
         Assert.Equal(expected, expected.Select(_ => backoff.Next()));
diff --git a/backend/agent/tests/MoShiro.Agent.Tests/LinkStateTests.cs b/backend/agent/tests/MoShiro.Agent.Tests/LinkStateTests.cs
index 32b386d..02a845f 100644
--- a/backend/agent/tests/MoShiro.Agent.Tests/LinkStateTests.cs
+++ b/backend/agent/tests/MoShiro.Agent.Tests/LinkStateTests.cs
@@ -16,6 +16,10 @@ public sealed class LinkStateTests
         int[] seconds = [1, 2, 3, 5, 5, 5];
         Assert.Equal(seconds, seconds.Select(_ => (int)backoff.Next().TotalSeconds));
 
+        // 连续失败很多次（路径是死的）：翻倍退避，最长五分钟
+        int[] later = [.. Enumerable.Range(0, 12).Select(_ => (int)backoff.Next().TotalSeconds)];
+        Assert.Equal([5, 5, 5, 10, 20, 40, 80, 160, 300], later[3..]);
+
         backoff.Reset();
 
         Assert.Equal(TimeSpan.FromSeconds(1), backoff.Next());