diff --git a/squinnondation/messages.py b/squinnondation/messages.py
index 4cc6488..5b8c4f8 100644
--- a/squinnondation/messages.py
+++ b/squinnondation/messages.py
@@ -176,6 +176,9 @@ class HelloTLV(TLV):
                                         f"the id {self.source_id}.")
             sender.id = self.source_id
 
+        if self.source_id == user.id:
+            sender.marked_as_banned = True
+
         if not sender.active:
             sender.id = self.source_id  # The sender we are given misses an id
             time_hl = time.time()
diff --git a/squinnondation/peers.py b/squinnondation/peers.py
index 8d37222..584b86f 100644
--- a/squinnondation/peers.py
+++ b/squinnondation/peers.py
@@ -26,6 +26,7 @@ class Peer:
         self.symmetric = False
         self.active = False
         self.errors = 0
+        self.marked_as_banned = False
 
         try:
             # Resolve DNS as an IPv6
@@ -60,7 +61,7 @@ class Peer:
         """
         If a client send more than 5 invalid packets, we don't trust it anymore.
         """
-        return self.errors >= 5
+        return self.errors >= 5 or self.marked_as_banned
 
     def __repr__(self):
         return self.nickname or str(self.id) or str(self.main_address)
@@ -79,6 +80,7 @@ class Peer:
         self.addresses.update(self.addresses)
         self.addresses.update(other.addresses)
         self.id = self.id if self.id > 0 else other.id
+        self.marked_as_banned = other.marked_as_banned
         return self