diff --git a/net/tcp/tcp_conn.c b/net/tcp/tcp_conn.c
index b9cfa904b0a..1c5ce4eb433 100644
--- a/net/tcp/tcp_conn.c
+++ b/net/tcp/tcp_conn.c
@@ -325,6 +325,12 @@ static inline int tcp_ipv4_bind(FAR struct tcp_conn_s *conn,
 
   net_lock();
 
+  if (conn->lport != 0)
+    {
+      net_unlock();
+      return -EINVAL;
+    }
+
   /* Verify or select a local port (network byte order) */
 
   port = tcp_selectport(PF_INET,
@@ -390,6 +396,12 @@ static inline int tcp_ipv6_bind(FAR struct tcp_conn_s *conn,
 
   net_lock();
 
+  if (conn->lport != 0)
+    {
+      net_unlock();
+      return -EINVAL;
+    }
+
   /* Verify or select a local port (network byte order) */
 
   /* The port number must be unique for this address binding */