diff --git a/daemon/core/grpc/server.py b/daemon/core/grpc/server.py
index 2511d9f8..2d1255a2 100644
--- a/daemon/core/grpc/server.py
+++ b/daemon/core/grpc/server.py
@@ -130,14 +130,14 @@ class CoreGrpcServer(core_pb2_grpc.CoreApiServicer):
     def get_session(self, _id, context):
         session = self.coreemu.sessions.get(_id)
         if not session:
-            context.abort(grpc.StatusCode.NOT_FOUND, "session not found")
+            context.abort(grpc.StatusCode.NOT_FOUND, "session {} not found".format(_id))
         return session
 
     def get_node(self, session, _id, context):
-        node = session.get_object(_id)
-        if not node:
-            context.abort(grpc.StatusCode.NOT_FOUND, "node not found")
-        return node
+        try:
+            return session.get_object(_id)
+        except KeyError:
+            context.abort(grpc.StatusCode.NOT_FOUND, "node {} not found".format(_id))
 
     def CreateSession(self, request, context):
         logging.debug("create session: %s", request)
@@ -509,6 +509,10 @@ class CoreGrpcServer(core_pb2_grpc.CoreApiServicer):
     def AddLink(self, request, context):
         logging.debug("add link: %s", request)
         session = self.get_session(request.session, context)
+
+        # validate node exist
+        self.get_node(session, request.link.node_one, context)
+        self.get_node(session, request.link.node_two, context)
         node_one = request.link.node_one
         node_two = request.link.node_two
 
diff --git a/daemon/tests/test_grpc.py b/daemon/tests/test_grpc.py
index 74aeeec1..af06fde9 100644
--- a/daemon/tests/test_grpc.py
+++ b/daemon/tests/test_grpc.py
@@ -2,6 +2,7 @@ import time
 
 from Queue import Queue
 
+import grpc
 import pytest
 
 from core.conf import ConfigShim
@@ -47,18 +48,24 @@ class TestGrpc:
             assert response.id == session_id
             assert session.session_id == session_id
 
-    def test_delete_session(self, grpc_server):
+    @pytest.mark.parametrize("session_id, expected", [
+        (None, True),
+        (6013, False)
+    ])
+    def test_delete_session(self, grpc_server, session_id, expected):
         # given
         client = CoreGrpcClient()
         session = grpc_server.coreemu.create_session()
+        if session_id is None:
+            session_id = session.session_id
 
         # then
         with client.context_connect():
-            response = client.delete_session(session.session_id)
+            response = client.delete_session(session_id)
 
         # then
-        assert response.result is True
-        assert grpc_server.coreemu.sessions.get(session.session_id) is None
+        assert response.result is expected
+        assert grpc_server.coreemu.sessions.get(session_id) is None
 
     def test_get_session(self, grpc_server):
         # given
@@ -203,7 +210,11 @@ class TestGrpc:
         # then
         assert response.node.id == node.objid
 
-    def test_edit_node(self, grpc_server):
+    @pytest.mark.parametrize("node_id, expected", [
+        (1, True),
+        (2, False)
+    ])
+    def test_edit_node(self, grpc_server, node_id, expected):
         # given
         client = CoreGrpcClient()
         session = grpc_server.coreemu.create_session()
@@ -214,14 +225,19 @@ class TestGrpc:
         with client.context_connect():
             node_options = NodeOptions()
             node_options.set_position(x, y)
-            response = client.edit_node(session.session_id, node.objid, node_options)
+            response = client.edit_node(session.session_id, node_id, node_options)
 
         # then
-        assert response.result is True
-        assert node.position.x == x
-        assert node.position.y == y
+        assert response.result is expected
+        if expected is True:
+            assert node.position.x == x
+            assert node.position.y == y
 
-    def test_delete_node(self, grpc_server):
+    @pytest.mark.parametrize("node_id, expected", [
+        (1, True),
+        (2, False)
+    ])
+    def test_delete_node(self, grpc_server, node_id, expected):
         # given
         client = CoreGrpcClient()
         session = grpc_server.coreemu.create_session()
@@ -229,12 +245,13 @@ class TestGrpc:
 
         # then
         with client.context_connect():
-            response = client.delete_node(session.session_id, node.objid)
+            response = client.delete_node(session.session_id, node_id)
 
         # then
-        assert response.result is True
-        with pytest.raises(KeyError):
-            assert session.get_object(node.objid)
+        assert response.result is expected
+        if expected is True:
+            with pytest.raises(KeyError):
+                assert session.get_object(node.objid)
 
     def test_get_hooks(self, grpc_server):
         # given
@@ -313,6 +330,20 @@ class TestGrpc:
         # then
         assert len(response.links) == 1
 
+    def test_get_node_links_exception(self, grpc_server, ip_prefixes):
+        # given
+        client = CoreGrpcClient()
+        session = grpc_server.coreemu.create_session()
+        switch = session.add_node(_type=NodeTypes.SWITCH)
+        node = session.add_node()
+        interface = ip_prefixes.create_interface(node)
+        session.add_link(node.objid, switch.objid, interface)
+
+        # then
+        with pytest.raises(grpc.RpcError):
+            with client.context_connect():
+                client.get_node_links(session.session_id, 3)
+
     def test_add_link(self, grpc_server, ip_prefixes):
         # given
         client = CoreGrpcClient()
@@ -330,6 +361,18 @@ class TestGrpc:
         assert response.result is True
         assert len(switch.all_link_data(0)) == 1
 
+    def test_add_link_exception(self, grpc_server, ip_prefixes):
+        # given
+        client = CoreGrpcClient()
+        session = grpc_server.coreemu.create_session()
+        node = session.add_node()
+
+        # then
+        interface = ip_prefixes.create_interface(node)
+        with pytest.raises(grpc.RpcError):
+            with client.context_connect():
+                client.add_link(session.session_id, 1, 3, interface)
+
     def test_edit_link(self, grpc_server, ip_prefixes):
         # given
         client = CoreGrpcClient()