From 6e0f58051cb45041f0438181a269c6fd03573cdc Mon Sep 17 00:00:00 2001
From: DarkLord017 <sambhavjain170944@gmail.com>
Date: Tue, 23 Jun 2026 01:26:08 +0530
Subject: [PATCH 01/14] fix: prevent discovery eviction from disconnecting
 active sync peer

---
 src/Nethermind/Nethermind.Network/PeerPool.cs      | 11 ++++++++++-
 src/Nethermind/Nethermind.Network/Rlpx/RlpxHost.cs | 10 ++++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/Nethermind/Nethermind.Network/PeerPool.cs b/src/Nethermind/Nethermind.Network/PeerPool.cs
index 629be9fa089c..f1bbbf84af9f 100644
--- a/src/Nethermind/Nethermind.Network/PeerPool.cs
+++ b/src/Nethermind/Nethermind.Network/PeerPool.cs
@@ -74,7 +74,16 @@ public PeerPool(
             _nodeSource.NodeRemoved += NodeSourceOnNodeRemoved;
         }
 
-        private void NodeSourceOnNodeRemoved(object? sender, NodeEventArgs e) => TryRemove(e.Node.Id, out _);
+        private void NodeSourceOnNodeRemoved(object? sender, NodeEventArgs e)
+        {
+            if (Peers.TryGetValue(e.Node.Id, out Peer? peer)
+                && (peer.InSession is not null || peer.OutSession is not null))
+            {
+                return;
+            }
+
+            TryRemove(e.Node.Id, out _);
+        }
 
         public Peer GetOrAdd(Node node) => Peers.GetOrAdd(node.Id, valueFactory: _createNewNodePeer, (node, _staticPeers));
 
diff --git a/src/Nethermind/Nethermind.Network/Rlpx/RlpxHost.cs b/src/Nethermind/Nethermind.Network/Rlpx/RlpxHost.cs
index c0a64eb92c41..9a3d4f071f36 100644
--- a/src/Nethermind/Nethermind.Network/Rlpx/RlpxHost.cs
+++ b/src/Nethermind/Nethermind.Network/Rlpx/RlpxHost.cs
@@ -107,7 +107,7 @@ public RlpxHost(
             _nodeFilter = NodeFilter.Create(networkConfig.MaxActivePeers, networkConfig.FilterPeersByRecentIp, networkConfig.FilterPeersBySameSubnet, ips.ExternalIp);
         }
 
-        public bool ShouldContact(IPAddress ip, bool exactOnly = false) => _nodeFilter.TryAccept(ip, exactOnly);
+        public bool ShouldContact(IPAddress ip, bool exactOnly = false) => _nodeFilter.CanAccept(ip, exactOnly);
 
         public async Task Init()
         {
@@ -257,7 +257,7 @@ internal SessionActivitySubscription TrackSessionActivity(ISession session)
 
         /// <summary>
         /// Rejects inbound connections from IPs already seen within the filter window.
-        /// Outgoing connections are filtered earlier by <see cref="ShouldContact"/> before <see cref="ConnectAsync"/>.
+        /// Outgoing connections reserve their filter slot in <see cref="InitializeChannel"/> once the TCP channel is open.
         /// </summary>
         private bool ShouldRejectInbound(ISession session, IChannel channel)
         {
@@ -291,6 +291,12 @@ private void InitializeChannel(IChannel channel, ISession session)
                 return;
             }
 
+            if (session.Direction == ConnectionDirection.Out
+                && channel.RemoteAddress is IPEndPoint outboundEndpoint)
+            {
+                _nodeFilter.TryAccept(outboundEndpoint.Address);
+            }
+
             SetTcpSocketOptions(channel);
 
             TrackSessionActivity(session);

From 7d1133008258caef7aa2ff3b88e6cf99f760cddb Mon Sep 17 00:00:00 2001
From: DarkLord017 <sambhavjain170944@gmail.com>
Date: Tue, 23 Jun 2026 01:51:56 +0530
Subject: [PATCH 02/14] revert: remove false positive NodeFilter fix from
 RlpxHost

---
 src/Nethermind/Nethermind.Network/Rlpx/RlpxHost.cs | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/src/Nethermind/Nethermind.Network/Rlpx/RlpxHost.cs b/src/Nethermind/Nethermind.Network/Rlpx/RlpxHost.cs
index 9a3d4f071f36..c0a64eb92c41 100644
--- a/src/Nethermind/Nethermind.Network/Rlpx/RlpxHost.cs
+++ b/src/Nethermind/Nethermind.Network/Rlpx/RlpxHost.cs
@@ -107,7 +107,7 @@ public RlpxHost(
             _nodeFilter = NodeFilter.Create(networkConfig.MaxActivePeers, networkConfig.FilterPeersByRecentIp, networkConfig.FilterPeersBySameSubnet, ips.ExternalIp);
         }
 
-        public bool ShouldContact(IPAddress ip, bool exactOnly = false) => _nodeFilter.CanAccept(ip, exactOnly);
+        public bool ShouldContact(IPAddress ip, bool exactOnly = false) => _nodeFilter.TryAccept(ip, exactOnly);
 
         public async Task Init()
         {
@@ -257,7 +257,7 @@ internal SessionActivitySubscription TrackSessionActivity(ISession session)
 
         /// <summary>
         /// Rejects inbound connections from IPs already seen within the filter window.
-        /// Outgoing connections reserve their filter slot in <see cref="InitializeChannel"/> once the TCP channel is open.
+        /// Outgoing connections are filtered earlier by <see cref="ShouldContact"/> before <see cref="ConnectAsync"/>.
         /// </summary>
         private bool ShouldRejectInbound(ISession session, IChannel channel)
         {
@@ -291,12 +291,6 @@ private void InitializeChannel(IChannel channel, ISession session)
                 return;
             }
 
-            if (session.Direction == ConnectionDirection.Out
-                && channel.RemoteAddress is IPEndPoint outboundEndpoint)
-            {
-                _nodeFilter.TryAccept(outboundEndpoint.Address);
-            }
-
             SetTcpSocketOptions(channel);
 
             TrackSessionActivity(session);

From d9a5a13c491bea231ca968b419e7cd6bde59b58e Mon Sep 17 00:00:00 2001
From: DarkLord017 <sambhavjain170944@gmail.com>
Date: Tue, 23 Jun 2026 02:12:10 +0530
Subject: [PATCH 03/14] fix: race conditions

---
 src/Nethermind/Nethermind.Network/Peer.cs       |  7 +++++--
 .../Nethermind.Network/PeerManager.cs           | 17 ++++++++++-------
 src/Nethermind/Nethermind.Network/PeerPool.cs   | 12 +++++++++---
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/src/Nethermind/Nethermind.Network/Peer.cs b/src/Nethermind/Nethermind.Network/Peer.cs
index 5df8d0b3d53e..57c82df41ad7 100644
--- a/src/Nethermind/Nethermind.Network/Peer.cs
+++ b/src/Nethermind/Nethermind.Network/Peer.cs
@@ -30,15 +30,18 @@ public sealed class Peer(Node node, INodeStats? stats = null) : IEquatable<Peer>
 
         internal INodeStats? Stats { get; } = stats;
 
+        private volatile ISession? _inSession;
+        private volatile ISession? _outSession;
+
         /// <summary>
         /// An incoming session to the Node which can be in one of many states.
         /// </summary>
-        public ISession? InSession { get; set; }
+        public ISession? InSession { get => _inSession; set => _inSession = value; }
 
         /// <summary>
         /// An outgoing session to the Node which can be in one of many states.
         /// </summary>
-        public ISession? OutSession { get; set; }
+        public ISession? OutSession { get => _outSession; set => _outSession = value; }
 
         public override string ToString() => $"[Peer|{Node:s}|{InSession}|{OutSession}]";
 
diff --git a/src/Nethermind/Nethermind.Network/PeerManager.cs b/src/Nethermind/Nethermind.Network/PeerManager.cs
index 7c405d90563a..4cc8c50c2290 100644
--- a/src/Nethermind/Nethermind.Network/PeerManager.cs
+++ b/src/Nethermind/Nethermind.Network/PeerManager.cs
@@ -1075,14 +1075,17 @@ private bool CanAttachSessionDirectly(ISession session, Peer peer)
 
         private void AttachSession(Peer peer, ISession session, ConnectionDirection sessionDirection, bool disconnectOpposite)
         {
-            if (sessionDirection == ConnectionDirection.In)
+            lock (peer)
             {
-                peer.Stats.AddNodeStatsHandshakeEvent(ConnectionDirection.In);
-                peer.InSession = session;
-            }
-            else
-            {
-                peer.OutSession = session;
+                if (sessionDirection == ConnectionDirection.In)
+                {
+                    peer.Stats.AddNodeStatsHandshakeEvent(ConnectionDirection.In);
+                    peer.InSession = session;
+                }
+                else
+                {
+                    peer.OutSession = session;
+                }
             }
 
             if (disconnectOpposite)
diff --git a/src/Nethermind/Nethermind.Network/PeerPool.cs b/src/Nethermind/Nethermind.Network/PeerPool.cs
index f1bbbf84af9f..f97661caea59 100644
--- a/src/Nethermind/Nethermind.Network/PeerPool.cs
+++ b/src/Nethermind/Nethermind.Network/PeerPool.cs
@@ -76,13 +76,19 @@ public PeerPool(
 
         private void NodeSourceOnNodeRemoved(object? sender, NodeEventArgs e)
         {
-            if (Peers.TryGetValue(e.Node.Id, out Peer? peer)
-                && (peer.InSession is not null || peer.OutSession is not null))
+            if (!Peers.TryGetValue(e.Node.Id, out Peer? peer))
             {
+                TryRemove(e.Node.Id, out _);
                 return;
             }
 
-            TryRemove(e.Node.Id, out _);
+            lock (peer)
+            {
+                if (peer.InSession is not null || peer.OutSession is not null)
+                    return;
+
+                TryRemove(e.Node.Id, out _);
+            }
         }
 
         public Peer GetOrAdd(Node node) => Peers.GetOrAdd(node.Id, valueFactory: _createNewNodePeer, (node, _staticPeers));

From 31b2c4426c95735a0b64d70a8f46db2d19080701 Mon Sep 17 00:00:00 2001
From: DarkLord017 <sambhavjain170944@gmail.com>
Date: Tue, 23 Jun 2026 02:25:33 +0530
Subject: [PATCH 04/14] only remove when kamelia

---
 src/Nethermind/Nethermind.Network/PeerPool.cs | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/src/Nethermind/Nethermind.Network/PeerPool.cs b/src/Nethermind/Nethermind.Network/PeerPool.cs
index f97661caea59..d932cfc63870 100644
--- a/src/Nethermind/Nethermind.Network/PeerPool.cs
+++ b/src/Nethermind/Nethermind.Network/PeerPool.cs
@@ -17,6 +17,7 @@
 using Nethermind.Logging;
 using Nethermind.Network.Config;
 using Nethermind.Network.P2P;
+using Nethermind.Network.StaticNodes;
 using Nethermind.Stats;
 using Nethermind.Stats.Model;
 
@@ -76,19 +77,17 @@ public PeerPool(
 
         private void NodeSourceOnNodeRemoved(object? sender, NodeEventArgs e)
         {
-            if (!Peers.TryGetValue(e.Node.Id, out Peer? peer))
+            if (sender is not StaticNodesManager and not TrustedNodesManager
+                && Peers.TryGetValue(e.Node.Id, out Peer? peer))
             {
-                TryRemove(e.Node.Id, out _);
-                return;
+                lock (peer)
+                {
+                    if (peer.InSession is not null || peer.OutSession is not null)
+                        return;
+                }
             }
 
-            lock (peer)
-            {
-                if (peer.InSession is not null || peer.OutSession is not null)
-                    return;
-
-                TryRemove(e.Node.Id, out _);
-            }
+            TryRemove(e.Node.Id, out _);
         }
 
         public Peer GetOrAdd(Node node) => Peers.GetOrAdd(node.Id, valueFactory: _createNewNodePeer, (node, _staticPeers));

From 740e536daf8c1e95c4f122186126bc2c4709e3ce Mon Sep 17 00:00:00 2001
From: DarkLord017 <sambhavjain170944@gmail.com>
Date: Tue, 23 Jun 2026 02:33:04 +0530
Subject: [PATCH 05/14] fix race condition & tests

---
 src/Nethermind/Nethermind.Network/PeerPool.cs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/Nethermind/Nethermind.Network/PeerPool.cs b/src/Nethermind/Nethermind.Network/PeerPool.cs
index d932cfc63870..d28c1a01a71f 100644
--- a/src/Nethermind/Nethermind.Network/PeerPool.cs
+++ b/src/Nethermind/Nethermind.Network/PeerPool.cs
@@ -17,7 +17,7 @@
 using Nethermind.Logging;
 using Nethermind.Network.Config;
 using Nethermind.Network.P2P;
-using Nethermind.Network.StaticNodes;
+
 using Nethermind.Stats;
 using Nethermind.Stats.Model;
 
@@ -77,12 +77,12 @@ public PeerPool(
 
         private void NodeSourceOnNodeRemoved(object? sender, NodeEventArgs e)
         {
-            if (sender is not StaticNodesManager and not TrustedNodesManager
+            if (sender is not IStaticNodesManager and not ITrustedNodesManager
                 && Peers.TryGetValue(e.Node.Id, out Peer? peer))
             {
                 lock (peer)
                 {
-                    if (peer.InSession is not null || peer.OutSession is not null)
+                    if (peer.InSession is not null || peer.OutSession is not null || peer.IsAwaitingConnection)
                         return;
                 }
             }

From a0e62d52cda723a2fe0e8a43ada981452f28fa59 Mon Sep 17 00:00:00 2001
From: DarkLord017 <sambhavjain170944@gmail.com>
Date: Tue, 23 Jun 2026 02:34:13 +0530
Subject: [PATCH 06/14] fix race condition & tests

---
 src/Nethermind/Nethermind.Network/PeerPool.cs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/Nethermind/Nethermind.Network/PeerPool.cs b/src/Nethermind/Nethermind.Network/PeerPool.cs
index d28c1a01a71f..2fec8d5f999b 100644
--- a/src/Nethermind/Nethermind.Network/PeerPool.cs
+++ b/src/Nethermind/Nethermind.Network/PeerPool.cs
@@ -77,8 +77,10 @@ public PeerPool(
 
         private void NodeSourceOnNodeRemoved(object? sender, NodeEventArgs e)
         {
-            if (sender is not IStaticNodesManager and not ITrustedNodesManager
-                && Peers.TryGetValue(e.Node.Id, out Peer? peer))
+            if (!Peers.TryGetValue(e.Node.Id, out Peer? peer))
+                return;
+
+            if (sender is not IStaticNodesManager and not ITrustedNodesManager)
             {
                 lock (peer)
                 {

From 453baaded16f55a0e93f5d033bb29ce11ad78780 Mon Sep 17 00:00:00 2001
From: DarkLord017 <sambhavjain170944@gmail.com>
Date: Tue, 23 Jun 2026 02:39:59 +0530
Subject: [PATCH 07/14] fix race condition & tests

---
 src/Nethermind/Nethermind.Network/PeerPool.cs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/Nethermind/Nethermind.Network/PeerPool.cs b/src/Nethermind/Nethermind.Network/PeerPool.cs
index 2fec8d5f999b..868590a93120 100644
--- a/src/Nethermind/Nethermind.Network/PeerPool.cs
+++ b/src/Nethermind/Nethermind.Network/PeerPool.cs
@@ -17,7 +17,6 @@
 using Nethermind.Logging;
 using Nethermind.Network.Config;
 using Nethermind.Network.P2P;
-
 using Nethermind.Stats;
 using Nethermind.Stats.Model;
 
@@ -86,7 +85,10 @@ private void NodeSourceOnNodeRemoved(object? sender, NodeEventArgs e)
                 {
                     if (peer.InSession is not null || peer.OutSession is not null || peer.IsAwaitingConnection)
                         return;
+
+                    TryRemove(e.Node.Id, out _);
                 }
+                return;
             }
 
             TryRemove(e.Node.Id, out _);

From 6aaeda3666a7ab033df31294927b2f8a215145f9 Mon Sep 17 00:00:00 2001
From: Sambhav Jain <136801346+DarkLord017@users.noreply.github.com>
Date: Tue, 23 Jun 2026 02:47:56 +0530
Subject: [PATCH 08/14] Update src/Nethermind/Nethermind.Network/PeerPool.cs

Co-authored-by: claude[bot] <209825114+claude[bot]@users.noreply.github.com>
---
 src/Nethermind/Nethermind.Network/PeerPool.cs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/Nethermind/Nethermind.Network/PeerPool.cs b/src/Nethermind/Nethermind.Network/PeerPool.cs
index 868590a93120..fea90b7abb64 100644
--- a/src/Nethermind/Nethermind.Network/PeerPool.cs
+++ b/src/Nethermind/Nethermind.Network/PeerPool.cs
@@ -81,7 +81,13 @@ private void NodeSourceOnNodeRemoved(object? sender, NodeEventArgs e)
 
             if (sender is not IStaticNodesManager and not ITrustedNodesManager)
             {
-                lock (peer)
+            // Lock peer to make the session check and TryRemove atomic against AttachSession.
+            // If a session is being concurrently assigned, AttachSession also holds lock(peer),
+            // so only one thread will see null sessions and call TryRemove. Residual: TryGetValue
+            // is outside the lock, so a session assigned between TryGetValue and lock acquisition
+            // leaves the peer alive in ActivePeers but absent from Peers until rediscovery —
+            // strictly better than the original unconditional disconnect.
+            lock (peer)
                 {
                     if (peer.InSession is not null || peer.OutSession is not null || peer.IsAwaitingConnection)
                         return;

From 27a80d46ec6d1557d3fc193cb42c2dd3da1613c0 Mon Sep 17 00:00:00 2001
From: DarkLord017 <sambhavjain170944@gmail.com>
Date: Tue, 23 Jun 2026 02:50:14 +0530
Subject: [PATCH 09/14] fix linting

---
 src/Nethermind/Nethermind.Network/PeerPool.cs | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/Nethermind/Nethermind.Network/PeerPool.cs b/src/Nethermind/Nethermind.Network/PeerPool.cs
index fea90b7abb64..6972e5d0c459 100644
--- a/src/Nethermind/Nethermind.Network/PeerPool.cs
+++ b/src/Nethermind/Nethermind.Network/PeerPool.cs
@@ -81,13 +81,13 @@ private void NodeSourceOnNodeRemoved(object? sender, NodeEventArgs e)
 
             if (sender is not IStaticNodesManager and not ITrustedNodesManager)
             {
-            // Lock peer to make the session check and TryRemove atomic against AttachSession.
-            // If a session is being concurrently assigned, AttachSession also holds lock(peer),
-            // so only one thread will see null sessions and call TryRemove. Residual: TryGetValue
-            // is outside the lock, so a session assigned between TryGetValue and lock acquisition
-            // leaves the peer alive in ActivePeers but absent from Peers until rediscovery —
-            // strictly better than the original unconditional disconnect.
-            lock (peer)
+                // Lock peer to make the session check and TryRemove atomic against AttachSession.
+                // If a session is being concurrently assigned, AttachSession also holds lock(peer),
+                // so only one thread will see null sessions and call TryRemove. Residual: TryGetValue
+                // is outside the lock, so a session assigned between TryGetValue and lock acquisition
+                // leaves the peer alive in ActivePeers but absent from Peers until rediscovery —
+                // strictly better than the original unconditional disconnect.
+                lock (peer)
                 {
                     if (peer.InSession is not null || peer.OutSession is not null || peer.IsAwaitingConnection)
                         return;

From fed6fc5d975f2380c3584f6b3dab2c2d9efd05b1 Mon Sep 17 00:00:00 2001
From: Sambhav Jain <136801346+DarkLord017@users.noreply.github.com>
Date: Tue, 23 Jun 2026 17:13:12 +0530
Subject: [PATCH 10/14] Update src/Nethermind/Nethermind.Network/PeerPool.cs

Co-authored-by: Lukasz Rozmej <lukasz.rozmej@gmail.com>
---
 src/Nethermind/Nethermind.Network/PeerPool.cs | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/src/Nethermind/Nethermind.Network/PeerPool.cs b/src/Nethermind/Nethermind.Network/PeerPool.cs
index 6972e5d0c459..868590a93120 100644
--- a/src/Nethermind/Nethermind.Network/PeerPool.cs
+++ b/src/Nethermind/Nethermind.Network/PeerPool.cs
@@ -81,12 +81,6 @@ private void NodeSourceOnNodeRemoved(object? sender, NodeEventArgs e)
 
             if (sender is not IStaticNodesManager and not ITrustedNodesManager)
             {
-                // Lock peer to make the session check and TryRemove atomic against AttachSession.
-                // If a session is being concurrently assigned, AttachSession also holds lock(peer),
-                // so only one thread will see null sessions and call TryRemove. Residual: TryGetValue
-                // is outside the lock, so a session assigned between TryGetValue and lock acquisition
-                // leaves the peer alive in ActivePeers but absent from Peers until rediscovery —
-                // strictly better than the original unconditional disconnect.
                 lock (peer)
                 {
                     if (peer.InSession is not null || peer.OutSession is not null || peer.IsAwaitingConnection)

From 29b21e76a33c9313293b6d13e1c29fba1e6405c1 Mon Sep 17 00:00:00 2001
From: DarkLord017 <sambhavjain170944@gmail.com>
Date: Tue, 23 Jun 2026 19:52:41 +0530
Subject: [PATCH 11/14] use events instead of checking sender and other req
 changes & tests

---
 .../Modules/DiscoveryModule.cs                |  1 +
 .../PeerManagerTests.cs                       |  2 +-
 .../Nethermind.Network.Test/PeerPoolTests.cs  | 31 ++++++++++++++++++
 .../Nethermind.Network/NodeEventArgs.cs       |  6 ++++
 .../Nethermind.Network/NodesManager.cs        | 17 ++++++++++
 src/Nethermind/Nethermind.Network/Peer.cs     | 11 +++++--
 .../Nethermind.Network/PeerManager.cs         |  2 +-
 src/Nethermind/Nethermind.Network/PeerPool.cs | 23 +++++++------
 .../StaticNodes/StaticNodesManager.cs         | 12 ++-----
 .../Nethermind.Network/TrustedNodesManager.cs | 32 +++----------------
 10 files changed, 83 insertions(+), 54 deletions(-)

diff --git a/src/Nethermind/Nethermind.Init/Modules/DiscoveryModule.cs b/src/Nethermind/Nethermind.Init/Modules/DiscoveryModule.cs
index fbb5c369fdce..a5f328879a8d 100644
--- a/src/Nethermind/Nethermind.Init/Modules/DiscoveryModule.cs
+++ b/src/Nethermind/Nethermind.Init/Modules/DiscoveryModule.cs
@@ -49,6 +49,7 @@ protected override void Load(ContainerBuilder builder)
                 new TrustedNodesManager(initConfig.TrustedNodesPath.GetApplicationResourcePath(initConfig.DataDir), logManager))
 
             .Bind<INodeSource, IStaticNodesManager>()
+            .Bind<INodeSource, ITrustedNodesManager>()
 
             // Used by NodesLoader, and ProtocolsManager which add entry on sync peer connected
             .AddNetworkStorage(DbNames.PeersDb, DbNames.PeersDb)
diff --git a/src/Nethermind/Nethermind.Network.Test/PeerManagerTests.cs b/src/Nethermind/Nethermind.Network.Test/PeerManagerTests.cs
index a2282a4abddd..61112405ed98 100644
--- a/src/Nethermind/Nethermind.Network.Test/PeerManagerTests.cs
+++ b/src/Nethermind/Nethermind.Network.Test/PeerManagerTests.cs
@@ -652,7 +652,7 @@ public async Task Will_disconnect_on_remove_static_node()
             void DisconnectHandler(object o, DisconnectEventArgs e) => disconnections++;
             ctx.Sessions.ForEach(s => s.Disconnected += DisconnectHandler);
 
-            ctx.StaticNodesManager.NodeRemoved += Raise.EventWith(new NodeEventArgs(
+            ctx.StaticNodesManager.NodeRemoved += Raise.EventWith<NodeEventArgs>(new ExplicitNodeRemovalEventArgs(
                 new Node(staticNodes.First())));
 
             Assert.That(ctx.PeerManager.ActivePeers.Count(p => p.Node.IsStatic), Is.EqualTo(nodesCount - 1));
diff --git a/src/Nethermind/Nethermind.Network.Test/PeerPoolTests.cs b/src/Nethermind/Nethermind.Network.Test/PeerPoolTests.cs
index d9339a6aefb6..7bb20f24bc7a 100644
--- a/src/Nethermind/Nethermind.Network.Test/PeerPoolTests.cs
+++ b/src/Nethermind/Nethermind.Network.Test/PeerPoolTests.cs
@@ -184,6 +184,37 @@ public async Task PeerPool_ShouldThrottleSource_WhenActivePeerPoolIsFull()
         }
     }
 
+    [Test]
+    public void PeerPool_DiscoveryEviction_KeepsPeer_WhenSessionActive()
+    {
+        ITrustedNodesManager trustedNodesManager = Substitute.For<ITrustedNodesManager>();
+        TestNodeSource nodeSource = new();
+        PeerPool pool = CreatePeerPool(nodeSource, trustedNodesManager, maxActivePeers: 10, maxCandidatePeerCount: 10);
+
+        Node node = new(TestItem.PublicKeyA, "1.2.3.4", 1234);
+        Peer peer = pool.GetOrAdd(node);
+        peer.InSession = Substitute.For<ISession>();
+
+        nodeSource.RemoveNode(node);
+
+        Assert.That(pool.TryGet(node.Id, out _), Is.True);
+    }
+
+    [Test]
+    public void PeerPool_DiscoveryEviction_RemovesPeer_WhenNoSession()
+    {
+        ITrustedNodesManager trustedNodesManager = Substitute.For<ITrustedNodesManager>();
+        TestNodeSource nodeSource = new();
+        PeerPool pool = CreatePeerPool(nodeSource, trustedNodesManager, maxActivePeers: 10, maxCandidatePeerCount: 10);
+
+        Node node = new(TestItem.PublicKeyA, "1.2.3.4", 1234);
+        pool.GetOrAdd(node);
+
+        nodeSource.RemoveNode(node);
+
+        Assert.That(pool.TryGet(node.Id, out _), Is.False);
+    }
+
     [Test]
     public void PeerPool_Replace_DoesNotInheritStaticFlag()
     {
diff --git a/src/Nethermind/Nethermind.Network/NodeEventArgs.cs b/src/Nethermind/Nethermind.Network/NodeEventArgs.cs
index 458f981771f9..390023f6c7b8 100644
--- a/src/Nethermind/Nethermind.Network/NodeEventArgs.cs
+++ b/src/Nethermind/Nethermind.Network/NodeEventArgs.cs
@@ -10,4 +10,10 @@ public class NodeEventArgs(Node node) : EventArgs
     {
         public Node Node { get; } = node;
     }
+
+    /// <summary>
+    /// Raised when a node is explicitly removed by the operator (e.g. via admin_removePeer).
+    /// Receivers must disconnect any active P2P session unconditionally.
+    /// </summary>
+    public class ExplicitNodeRemovalEventArgs(Node node) : NodeEventArgs(node);
 }
diff --git a/src/Nethermind/Nethermind.Network/NodesManager.cs b/src/Nethermind/Nethermind.Network/NodesManager.cs
index fa6dfc5740f5..194bf82ec25b 100644
--- a/src/Nethermind/Nethermind.Network/NodesManager.cs
+++ b/src/Nethermind/Nethermind.Network/NodesManager.cs
@@ -13,6 +13,7 @@
 using Nethermind.Core.Crypto;
 using Nethermind.Logging;
 using Nethermind.Serialization.Json;
+using Nethermind.Stats.Model;
 
 namespace Nethermind.Network;
 
@@ -132,6 +133,22 @@ protected virtual async Task<ConcurrentDictionary<PublicKey, NetworkNode>> Parse
         return nodes;
     }
 
+    public event EventHandler<NodeEventArgs>? NodeRemoved;
+
+    /// <summary>
+    /// Removes a node from the in-memory store and fires <see cref="NodeRemoved"/> as an
+    /// <see cref="ExplicitNodeRemovalEventArgs"/> so downstream listeners (e.g. <c>PeerPool</c>)
+    /// know to disconnect the peer unconditionally.
+    /// </summary>
+    protected bool TryRemoveNode(PublicKey nodeId)
+    {
+        if (!_nodes.TryRemove(nodeId, out NetworkNode? removed))
+            return false;
+
+        NodeRemoved?.Invoke(this, new ExplicitNodeRemovalEventArgs(new Node(removed)));
+        return true;
+    }
+
     protected virtual Task SaveFileAsync(CancellationToken cancellationToken = default)
     {
         ArgumentException.ThrowIfNullOrWhiteSpace(path);
diff --git a/src/Nethermind/Nethermind.Network/Peer.cs b/src/Nethermind/Nethermind.Network/Peer.cs
index 57c82df41ad7..13464aefe303 100644
--- a/src/Nethermind/Nethermind.Network/Peer.cs
+++ b/src/Nethermind/Nethermind.Network/Peer.cs
@@ -20,8 +20,6 @@ namespace Nethermind.Network
     /// </summary>
     public sealed class Peer(Node node, INodeStats? stats = null) : IEquatable<Peer>
     {
-        public bool IsAwaitingConnection { get; set; }
-
         /// <summary>
         /// A physical network node with a network address combined with information about the client version
         /// and any extra attributes that we assign to a network node (static / trusted / bootnode).
@@ -30,9 +28,18 @@ public sealed class Peer(Node node, INodeStats? stats = null) : IEquatable<Peer>
 
         internal INodeStats? Stats { get; } = stats;
 
+        /// <remarks>
+        /// Guards <see cref="IsAwaitingConnection"/>, <see cref="InSession"/>, and <see cref="OutSession"/>
+        /// as a unit. Using a dedicated object avoids locking on a publicly visible instance.
+        /// </remarks>
+        internal readonly object SessionLock = new();
+
+        private volatile bool _isAwaitingConnection;
         private volatile ISession? _inSession;
         private volatile ISession? _outSession;
 
+        public bool IsAwaitingConnection { get => _isAwaitingConnection; set => _isAwaitingConnection = value; }
+
         /// <summary>
         /// An incoming session to the Node which can be in one of many states.
         /// </summary>
diff --git a/src/Nethermind/Nethermind.Network/PeerManager.cs b/src/Nethermind/Nethermind.Network/PeerManager.cs
index 4cc8c50c2290..8635758fc961 100644
--- a/src/Nethermind/Nethermind.Network/PeerManager.cs
+++ b/src/Nethermind/Nethermind.Network/PeerManager.cs
@@ -1075,7 +1075,7 @@ private bool CanAttachSessionDirectly(ISession session, Peer peer)
 
         private void AttachSession(Peer peer, ISession session, ConnectionDirection sessionDirection, bool disconnectOpposite)
         {
-            lock (peer)
+            lock (peer.SessionLock)
             {
                 if (sessionDirection == ConnectionDirection.In)
                 {
diff --git a/src/Nethermind/Nethermind.Network/PeerPool.cs b/src/Nethermind/Nethermind.Network/PeerPool.cs
index 6972e5d0c459..8bd1d4a4b7e8 100644
--- a/src/Nethermind/Nethermind.Network/PeerPool.cs
+++ b/src/Nethermind/Nethermind.Network/PeerPool.cs
@@ -79,21 +79,20 @@ private void NodeSourceOnNodeRemoved(object? sender, NodeEventArgs e)
             if (!Peers.TryGetValue(e.Node.Id, out Peer? peer))
                 return;
 
-            if (sender is not IStaticNodesManager and not ITrustedNodesManager)
+            if (e is not ExplicitNodeRemovalEventArgs)
             {
-                // Lock peer to make the session check and TryRemove atomic against AttachSession.
-                // If a session is being concurrently assigned, AttachSession also holds lock(peer),
-                // so only one thread will see null sessions and call TryRemove. Residual: TryGetValue
-                // is outside the lock, so a session assigned between TryGetValue and lock acquisition
-                // leaves the peer alive in ActivePeers but absent from Peers until rediscovery —
-                // strictly better than the original unconditional disconnect.
-                lock (peer)
+                // Only remove the peer if no P2P session is active.
+                // The dictionary removals are done inside SessionLock so the session check and
+                // removal are atomic against AttachSession. PeerRemoved is fired outside the lock
+                // to avoid holding it across arbitrary event handler code.
+                bool removed;
+                lock (peer.SessionLock)
                 {
-                    if (peer.InSession is not null || peer.OutSession is not null || peer.IsAwaitingConnection)
-                        return;
-
-                    TryRemove(e.Node.Id, out _);
+                    removed = peer.InSession is null && peer.OutSession is null && !peer.IsAwaitingConnection
+                              && Peers.TryRemove(e.Node.Id, out _);
+                    if (removed) _staticPeers.TryRemove(e.Node.Id, out _);
                 }
+                if (removed) PeerRemoved?.Invoke(this, new PeerEventArgs(peer));
                 return;
             }
 
diff --git a/src/Nethermind/Nethermind.Network/StaticNodes/StaticNodesManager.cs b/src/Nethermind/Nethermind.Network/StaticNodes/StaticNodesManager.cs
index 7d91f9293c87..fb5434712fd6 100644
--- a/src/Nethermind/Nethermind.Network/StaticNodes/StaticNodesManager.cs
+++ b/src/Nethermind/Nethermind.Network/StaticNodes/StaticNodesManager.cs
@@ -52,20 +52,14 @@ public async Task<bool> AddAsync(NetworkNode networkNode, bool updateFile = true
 
     public async Task<bool> RemoveAsync(NetworkNode networkNode, bool updateFile = true, CancellationToken cancellationToken = default)
     {
-        if (!_nodes.TryRemove(networkNode.NodeId, out _))
+        if (!TryRemoveNode(networkNode.NodeId))
         {
             if (_logger.IsInfo) _logger.Info($"Static node was not found: {networkNode}");
             return false;
         }
 
         if (_logger.IsInfo) _logger.Info($"Static node was removed: {networkNode}");
-        Node node = new(networkNode);
-        NodeRemoved?.Invoke(this, new NodeEventArgs(node));
-        if (updateFile)
-        {
-            await SaveFileAsync(cancellationToken);
-        }
-
+        if (updateFile) await SaveFileAsync(cancellationToken);
         return true;
     }
 
@@ -101,6 +95,4 @@ public async IAsyncEnumerable<Node> DiscoverNodes([EnumeratorCancellation] Cance
     }
 
     private event EventHandler<NodeEventArgs>? NodeAdded;
-
-    public event EventHandler<NodeEventArgs>? NodeRemoved;
 }
diff --git a/src/Nethermind/Nethermind.Network/TrustedNodesManager.cs b/src/Nethermind/Nethermind.Network/TrustedNodesManager.cs
index 206c26f15b65..a6494c3d041f 100644
--- a/src/Nethermind/Nethermind.Network/TrustedNodesManager.cs
+++ b/src/Nethermind/Nethermind.Network/TrustedNodesManager.cs
@@ -84,40 +84,16 @@ public async Task<bool> AddAsync(Enode enode, bool updateFile = true, Cancellati
     public async Task<bool> RemoveAsync(Enode enode, bool updateFile = true, CancellationToken cancellationToken = default)
     {
         NetworkNode networkNode = new(enode);
-        if (!_nodes.TryRemove(networkNode.NodeId, out _))
+        if (!TryRemoveNode(networkNode.NodeId))
         {
-            if (_logger.IsInfo)
-            {
-                _logger.Info($"Trusted node was not found: {enode}");
-            }
+            if (_logger.IsInfo) _logger.Info($"Trusted node was not found: {enode}");
             return false;
         }
 
-        if (_logger.IsInfo)
-        {
-            _logger.Info($"Trusted node was removed: {enode}");
-        }
-
-        // Fire NodeRemoved (drives PeerPool disconnect via the event chain) BEFORE the file write,
-        // so a cancelled SaveFileAsync cannot leave the peer untrusted-in-memory yet still connected.
-        // Mirrors StaticNodesManager.RemoveAsync ordering.
-        OnNodeRemoved(networkNode);
-
-        if (updateFile)
-        {
-            await SaveFileAsync(cancellationToken);
-        }
-
+        if (_logger.IsInfo) _logger.Info($"Trusted node was removed: {enode}");
+        if (updateFile) await SaveFileAsync(cancellationToken);
         return true;
     }
 
     public bool IsTrusted(Enode enode) => _nodes.ContainsKey(enode.PublicKey);
-
-    public event EventHandler<NodeEventArgs>? NodeRemoved;
-
-    private void OnNodeRemoved(NetworkNode node)
-    {
-        Node nodeForEvent = new(node);
-        NodeRemoved?.Invoke(this, new NodeEventArgs(nodeForEvent));
-    }
 }

From 659a5f266189de90f4d276c2fc0db300cb2dd7c6 Mon Sep 17 00:00:00 2001
From: DarkLord017 <sambhavjain170944@gmail.com>
Date: Tue, 23 Jun 2026 20:01:12 +0530
Subject: [PATCH 12/14] linting

---
 src/Nethermind/Nethermind.Network/TrustedNodesManager.cs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Nethermind/Nethermind.Network/TrustedNodesManager.cs b/src/Nethermind/Nethermind.Network/TrustedNodesManager.cs
index a6494c3d041f..559811df32d2 100644
--- a/src/Nethermind/Nethermind.Network/TrustedNodesManager.cs
+++ b/src/Nethermind/Nethermind.Network/TrustedNodesManager.cs
@@ -5,7 +5,6 @@
 using Nethermind.Core.Crypto;
 using Nethermind.Logging;
 using Nethermind.Stats.Model;
-using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
@@ -84,6 +83,8 @@ public async Task<bool> AddAsync(Enode enode, bool updateFile = true, Cancellati
     public async Task<bool> RemoveAsync(Enode enode, bool updateFile = true, CancellationToken cancellationToken = default)
     {
         NetworkNode networkNode = new(enode);
+        // Fire NodeRemoved BEFORE the file write: a cancelled SaveFileAsync must not leave
+        // the peer disconnected in-memory but still persisted as trusted.
         if (!TryRemoveNode(networkNode.NodeId))
         {
             if (_logger.IsInfo) _logger.Info($"Trusted node was not found: {enode}");

From befc7fda2521031b8dcdc67212c5a1450fdbc315 Mon Sep 17 00:00:00 2001
From: DarkLord017 <sambhavjain170944@gmail.com>
Date: Tue, 23 Jun 2026 20:19:50 +0530
Subject: [PATCH 13/14] merge to cases

---
 .../Nethermind.Network.Test/PeerPoolTests.cs  | 24 ++++---------------
 src/Nethermind/Nethermind.Network/PeerPool.cs | 13 +++++-----
 2 files changed, 12 insertions(+), 25 deletions(-)

diff --git a/src/Nethermind/Nethermind.Network.Test/PeerPoolTests.cs b/src/Nethermind/Nethermind.Network.Test/PeerPoolTests.cs
index 7bb20f24bc7a..794dcf0aa0cb 100644
--- a/src/Nethermind/Nethermind.Network.Test/PeerPoolTests.cs
+++ b/src/Nethermind/Nethermind.Network.Test/PeerPoolTests.cs
@@ -184,8 +184,9 @@ public async Task PeerPool_ShouldThrottleSource_WhenActivePeerPoolIsFull()
         }
     }
 
-    [Test]
-    public void PeerPool_DiscoveryEviction_KeepsPeer_WhenSessionActive()
+    [TestCase(true, true)]   // active session → peer kept
+    [TestCase(false, false)] // no session → peer evicted
+    public void PeerPool_DiscoveryEviction(bool hasSession, bool expectPresent)
     {
         ITrustedNodesManager trustedNodesManager = Substitute.For<ITrustedNodesManager>();
         TestNodeSource nodeSource = new();
@@ -193,26 +194,11 @@ public void PeerPool_DiscoveryEviction_KeepsPeer_WhenSessionActive()
 
         Node node = new(TestItem.PublicKeyA, "1.2.3.4", 1234);
         Peer peer = pool.GetOrAdd(node);
-        peer.InSession = Substitute.For<ISession>();
-
-        nodeSource.RemoveNode(node);
-
-        Assert.That(pool.TryGet(node.Id, out _), Is.True);
-    }
-
-    [Test]
-    public void PeerPool_DiscoveryEviction_RemovesPeer_WhenNoSession()
-    {
-        ITrustedNodesManager trustedNodesManager = Substitute.For<ITrustedNodesManager>();
-        TestNodeSource nodeSource = new();
-        PeerPool pool = CreatePeerPool(nodeSource, trustedNodesManager, maxActivePeers: 10, maxCandidatePeerCount: 10);
-
-        Node node = new(TestItem.PublicKeyA, "1.2.3.4", 1234);
-        pool.GetOrAdd(node);
+        if (hasSession) peer.InSession = Substitute.For<ISession>();
 
         nodeSource.RemoveNode(node);
 
-        Assert.That(pool.TryGet(node.Id, out _), Is.False);
+        Assert.That(pool.TryGet(node.Id, out _), Is.EqualTo(expectPresent));
     }
 
     [Test]
diff --git a/src/Nethermind/Nethermind.Network/PeerPool.cs b/src/Nethermind/Nethermind.Network/PeerPool.cs
index 8bd1d4a4b7e8..7883f5005239 100644
--- a/src/Nethermind/Nethermind.Network/PeerPool.cs
+++ b/src/Nethermind/Nethermind.Network/PeerPool.cs
@@ -137,18 +137,19 @@ private Peer CreateNew(PublicKeyAsKey key, (NetworkNode Node, ConcurrentDictiona
 
         public bool TryRemove(PublicKey id, out Peer peer)
         {
-            if (Peers.TryRemove(id, out peer))
+            if (!Peers.TryRemove(id, out peer))
+                return false;
+
+            _staticPeers.TryRemove(id, out _);
+            lock (peer.SessionLock)
             {
-                _staticPeers.TryRemove(id, out _);
                 peer.InSession?.MarkDisconnected(DisconnectReason.PeerRemoved, DisconnectType.Local, "admin_removePeer");
                 peer.OutSession?.MarkDisconnected(DisconnectReason.PeerRemoved, DisconnectType.Local, "admin_removePeer");
                 peer.InSession = null;
                 peer.OutSession = null;
-                PeerRemoved?.Invoke(this, new PeerEventArgs(peer));
-                return true;
             }
-
-            return false;
+            PeerRemoved?.Invoke(this, new PeerEventArgs(peer));
+            return true;
         }
 
         public Peer Replace(ISession session)

From 7b75f99ad84df3b5569ae9337b809d51b2eadebd Mon Sep 17 00:00:00 2001
From: DarkLord017 <sambhavjain170944@gmail.com>
Date: Tue, 23 Jun 2026 20:26:22 +0530
Subject: [PATCH 14/14] add summary

---
 src/Nethermind/Nethermind.Network/NodesManager.cs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/Nethermind/Nethermind.Network/NodesManager.cs b/src/Nethermind/Nethermind.Network/NodesManager.cs
index 194bf82ec25b..679f513d54f6 100644
--- a/src/Nethermind/Nethermind.Network/NodesManager.cs
+++ b/src/Nethermind/Nethermind.Network/NodesManager.cs
@@ -133,6 +133,9 @@ protected virtual async Task<ConcurrentDictionary<PublicKey, NetworkNode>> Parse
         return nodes;
     }
 
+    /// <summary>
+    /// Raised when a node is explicitly removed from this source.
+    /// </summary>
     public event EventHandler<NodeEventArgs>? NodeRemoved;
 
     /// <summary>