diff --git a/repos/os/src/server/nic_router/interface.cc b/repos/os/src/server/nic_router/interface.cc
index 7e2138458b..fe53083d00 100644
--- a/repos/os/src/server/nic_router/interface.cc
+++ b/repos/os/src/server/nic_router/interface.cc
@@ -509,6 +509,7 @@ void Interface::_try_emergency_free_quota()
 
 
 Packet_result Interface::_new_link(L3_protocol          const  protocol,
+                                   void                *const  prot_base,
                                    Domain                     &local_domain,
                                    Link_side_id         const &local,
                                    Port_allocator_guard       *remote_port_alloc_ptr,
@@ -521,8 +522,8 @@ Packet_result Interface::_new_link(L3_protocol          const  protocol,
 		retry_once<Out_of_ram, Out_of_caps>(
 			[&] {
 				new (_alloc)
-				Tcp_link { *this, local_domain, local, remote_port_alloc_ptr, remote_domain,
-				           remote, _timer, *_config_ptr, protocol, _tcp_stats }; },
+					Tcp_link { *this, local_domain, local, remote_port_alloc_ptr, remote_domain,
+					           remote, _timer, *_config_ptr, protocol, _tcp_stats, *(Tcp_packet *)prot_base }; },
 			[&] { _try_emergency_free_quota(); },
 			[&] {
 				_tcp_stats.refused_for_ram++;
@@ -666,7 +667,7 @@ Packet_result Interface::_nat_link_and_pass(Ethernet_frame         &eth,
 
 	Link_side_id const remote_id = { ip.dst(), _dst_port(prot, prot_base),
 	                                 ip.src(), _src_port(prot, prot_base) };
-	result = _new_link(prot, local_domain, local_id, remote_port_alloc_ptr, remote_domain, remote_id);
+	result = _new_link(prot, prot_base, local_domain, local_id, remote_port_alloc_ptr, remote_domain, remote_id);
 	if (result.valid())
 		return result;
 
diff --git a/repos/os/src/server/nic_router/interface.h b/repos/os/src/server/nic_router/interface.h
index d5524c827d..f580922c83 100644
--- a/repos/os/src/server/nic_router/interface.h
+++ b/repos/os/src/server/nic_router/interface.h
@@ -179,6 +179,7 @@ class Net::Interface : private Interface_list::Element
 		Interface &operator = (Interface const &);
 
 		[[nodiscard]] Packet_result _new_link(L3_protocol         const  protocol,
+		                                     void                *const  prot_base,
 		                                     Domain                     &local_domain,
 		                                     Link_side_id         const &local_id,
 		                                     Port_allocator_guard       *remote_port_alloc_ptr,
diff --git a/repos/os/src/server/nic_router/link.cc b/repos/os/src/server/nic_router/link.cc
index 4d6c8ff5f9..5e3080d9e9 100644
--- a/repos/os/src/server/nic_router/link.cc
+++ b/repos/os/src/server/nic_router/link.cc
@@ -205,11 +205,14 @@ Tcp_link::Tcp_link(Interface                  &cln_interface,
                    Cached_timer               &timer,
                    Configuration              &config,
                    L3_protocol          const  protocol,
-                   Interface_link_stats       &stats)
+                   Interface_link_stats       &stats,
+                   Tcp_packet                 &tcp)
 :
 	Link(cln_interface, cln_domain, cln_id, srv_port_alloc_ptr, srv_domain, srv_id, timer,
 	     config, protocol, config.tcp_idle_timeout(), stats)
-{ }
+{
+	client_packet(tcp);
+}
 
 
 void Tcp_link::_closing()
@@ -234,6 +237,9 @@ void Tcp_link::_tcp_packet(Tcp_packet &tcp,
                            Peer       &sender,
                            Peer       &receiver)
 {
+	if (_state == State::OPENING)
+		_opening_tcp_packet(tcp, sender, receiver);
+
 	if (_state == State::CLOSED) {
 		return; }
 
@@ -262,16 +268,19 @@ void Tcp_link::_tcp_packet(Tcp_packet &tcp,
 }
 
 
-void Tcp_link::server_packet(Tcp_packet &tcp)
+void Tcp_link::_opening_tcp_packet(Tcp_packet const &tcp, Peer &sender, Peer &receiver)
 {
-	if (_opening) {
+	if (tcp.syn())
+		sender.syn = true;
+	if (tcp.ack() && receiver.syn && !receiver.syn_acked)
+		receiver.syn_acked = true;
+	if (sender.syn_acked && receiver.syn_acked) {
 		_opening = false;
 		_state = State::OPEN;
 		(*_stats_ptr)--;
 		if (_stats_ptr == &_stats.opening) { _stats_ptr = &_stats.open; }
 		(*_stats_ptr)++;
 	}
-	_tcp_packet(tcp, _server, _client);
 }
 
 
diff --git a/repos/os/src/server/nic_router/link.h b/repos/os/src/server/nic_router/link.h
index a2a52bcfd3..493b9a039e 100644
--- a/repos/os/src/server/nic_router/link.h
+++ b/repos/os/src/server/nic_router/link.h
@@ -265,6 +265,8 @@ class Net::Tcp_link : public Link
 
 		struct Peer
 		{
+			bool syn       { false };
+			bool syn_acked { false };
 			bool fin       { false };
 			bool fin_acked { false };
 		};
@@ -277,26 +279,31 @@ class Net::Tcp_link : public Link
 		                 Peer       &sender,
 		                 Peer       &receiver);
 
+		void _opening_tcp_packet(Tcp_packet const &tcp,
+		                         Peer             &sender,
+		                         Peer             &receiver);
+
 		void _closing();
 
 		void _closed();
 
 	public:
 
-		Tcp_link(Interface                     &cln_interface,
-		         Domain                        &cln_domain,
-		         Link_side_id            const &cln_id,
-		         Port_allocator_guard          *srv_port_alloc_ptr,
-		         Domain                        &srv_domain,
-		         Link_side_id            const &srv_id,
-		         Cached_timer                  &timer,
-		         Configuration                 &config,
-		         L3_protocol             const  protocol,
-		         Interface_link_stats          &stats);
+		Tcp_link(Interface                 &cln_interface,
+		         Domain                    &cln_domain,
+		         Link_side_id        const &cln_id,
+		         Port_allocator_guard      *srv_port_alloc_ptr,
+		         Domain                    &srv_domain,
+		         Link_side_id        const &srv_id,
+		         Cached_timer              &timer,
+		         Configuration             &config,
+		         L3_protocol         const  protocol,
+		         Interface_link_stats      &stats,
+		         Tcp_packet                &tcp);
 
 		void client_packet(Tcp_packet &tcp) { _tcp_packet(tcp, _client, _server); }
 
-		void server_packet(Tcp_packet &tcp);
+		void server_packet(Tcp_packet &tcp) { _tcp_packet(tcp, _server, _client); }
 
 		bool can_early_drop() { return _state != State::OPEN; }
 };