diff --git a/src/Env/STM.hs b/src/Env/STM.hs
index 3d3ed522f..f651ca295 100644
--- a/src/Env/STM.hs
+++ b/src/Env/STM.hs
@@ -15,9 +15,15 @@ import Numeric.Natural
 import Transmission
 import UnliftIO.STM
 
-data Env = Env
+data Config = Config
   { tcpPort :: ServiceName,
     queueSize :: Natural,
+    connIdBytes :: Int,
+    msgIdBytes :: Int
+  }
+
+data Env = Env
+  { config :: Config,
     server :: Server,
     connStore :: STMConnStore,
     msgStore :: STMMsgStore,
@@ -48,10 +54,10 @@ newClient qSize = do
   sndQ <- newTBQueue qSize
   return Client {connections, rcvQ, sndQ}
 
-newEnv :: (MonadUnliftIO m, MonadRandom m) => String -> Natural -> m Env
-newEnv tcpPort queueSize = do
-  server <- atomically $ newServer queueSize
+newEnv :: (MonadUnliftIO m, MonadRandom m) => Config -> m Env
+newEnv config = do
+  server <- atomically $ newServer (queueSize config)
   connStore <- atomically newConnStore
   msgStore <- atomically newMsgStore
   idsDrg <- drgNew >>= newTVarIO
-  return Env {tcpPort, queueSize, server, connStore, msgStore, idsDrg}
+  return Env {config, server, connStore, msgStore, idsDrg}
diff --git a/src/Main.hs b/src/Main.hs
index 1c2f6f1e5..93356d90e 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -1,16 +1,18 @@
 module Main where
 
-import Network.Socket (ServiceName)
-import Numeric.Natural
+import Env.STM
 import Server (runSMPServer)
 
-port :: ServiceName
-port = "5223"
-
-queuePerClient :: Natural
-queuePerClient = 16
+cfg :: Config
+cfg =
+  Config
+    { tcpPort = "5223",
+      queueSize = 16,
+      connIdBytes = 12,
+      msgIdBytes = 6
+    }
 
 main :: IO ()
 main = do
-  putStrLn $ "Listening on port " ++ port
-  runSMPServer port queuePerClient
+  putStrLn $ "Listening on port " ++ tcpPort cfg
+  runSMPServer cfg
diff --git a/src/Server.hs b/src/Server.hs
index 16c0cf5a6..13d832778 100644
--- a/src/Server.hs
+++ b/src/Server.hs
@@ -25,8 +25,6 @@ import Data.Time.Clock
 import Env.STM
 import MsgStore
 import MsgStore.STM (MsgQueue)
-import Network.Socket
-import Numeric.Natural
 import Transmission
 import Transport
 import UnliftIO.Async
@@ -34,15 +32,15 @@ import UnliftIO.Concurrent
 import UnliftIO.IO
 import UnliftIO.STM
 
-runSMPServer :: (MonadRandom m, MonadUnliftIO m) => ServiceName -> Natural -> m ()
-runSMPServer port queueSize = do
-  env <- newEnv port queueSize
+runSMPServer :: (MonadRandom m, MonadUnliftIO m) => Config -> m ()
+runSMPServer cfg@Config {tcpPort} = do
+  env <- newEnv cfg
   runReaderT smpServer env
   where
     smpServer :: (MonadUnliftIO m, MonadReader Env m) => m ()
     smpServer = do
       s <- asks server
-      race_ (runTCPServer port runClient) (serverThread s)
+      race_ (runTCPServer tcpPort runClient) (serverThread s)
 
     serverThread :: MonadUnliftIO m => Server -> m ()
     serverThread Server {subscribedQ, connections} = forever . atomically $ do
@@ -56,7 +54,7 @@ runSMPServer port queueSize = do
 runClient :: (MonadUnliftIO m, MonadReader Env m) => Handle -> m ()
 runClient h = do
   putLn h "Welcome to SMP"
-  q <- asks queueSize
+  q <- asks $ queueSize . config
   c <- atomically $ newClient q
   s <- asks server
   raceAny_ [send h c, client c s, receive h c]
@@ -142,7 +140,9 @@ client clnt@Client {connections, rcvQ, sndQ} Server {subscribedQ} =
                   void $ subscribeConn rId
                   return $ IDS rId sId
                 Left e -> return $ ERR e
-            getIds = liftM2 (,) (randomId 16) (randomId 16)
+            getIds = do
+              n <- asks $ connIdBytes . config
+              liftM2 (,) (randomId n) (randomId n)
 
         subscribeConn :: RecipientId -> m Signed
         subscribeConn rId = do
@@ -166,14 +166,18 @@ client clnt@Client {connections, rcvQ, sndQ} Server {subscribedQ} =
           getConn st SSender sId
             >>= fmap (mkSigned sId) . either (return . ERR) storeMessage
           where
+            mkMessage :: m Message
+            mkMessage = do
+              msgId <- asks (msgIdBytes . config) >>= randomId
+              ts <- liftIO getCurrentTime
+              return $ Message {msgId, ts, msgBody}
+
             storeMessage :: Connection -> m (Command 'Broker)
             storeMessage c = case status c of
               ConnActive -> do
                 ms <- asks msgStore
                 q <- getMsgQueue ms (recipientId c)
-                msgId <- randomId 8
-                ts <- liftIO getCurrentTime
-                writeMsg q $ Message {msgId, ts, msgBody}
+                mkMessage >>= writeMsg q
                 return OK
               ConnOff -> return $ ERR AUTH
 
diff --git a/tests/SMPClient.hs b/tests/SMPClient.hs
index 84ca3a3e7..57977edef 100644
--- a/tests/SMPClient.hs
+++ b/tests/SMPClient.hs
@@ -5,8 +5,8 @@ module SMPClient where
 
 import Control.Monad.IO.Unlift
 import Crypto.Random
+import Env.STM
 import Network.Socket
-import Numeric.Natural
 import Server
 import Transmission
 import Transport
@@ -29,13 +29,19 @@ testPort = "5000"
 testHost :: HostName
 testHost = "localhost"
 
-queueSize :: Natural
-queueSize = 2
+cfg :: Config
+cfg =
+  Config
+    { tcpPort = testPort,
+      queueSize = 1,
+      connIdBytes = 12,
+      msgIdBytes = 6
+    }
 
 runSmpTest :: (MonadUnliftIO m, MonadRandom m) => (Handle -> m a) -> m a
 runSmpTest test =
   E.bracket
-    (forkIO $ runSMPServer testPort queueSize)
+    (forkIO $ runSMPServer cfg)
     (liftIO . killThread)
     \_ -> testSMPClient "localhost" testPort test