diff --git a/test/lwt/hash_server.ml b/test/lwt/hash_server.ml
index 0bae785c..a84f6ccb 100644
--- a/test/lwt/hash_server.ml
+++ b/test/lwt/hash_server.ml
@@ -211,8 +211,9 @@ let main ~port ~runner () : unit Lwt.t =
       Trace.message "exit handle client"
   in
 
-  let addr = Unix.ADDR_INET (Unix.inet_addr_any, port) in
+  let addr = Unix.ADDR_INET (Unix.inet_addr_loopback, port) in
   let _server = M_lwt.TCP_server.establish_lwt ~runner addr handle_client in
+  Printf.printf "listening on port=%d\n%!" port;
 
   lwt_fut
 
diff --git a/test/lwt/output_echo.expected b/test/lwt/output_echo.expected
index ddfd1845..4311fe1a 100644
--- a/test/lwt/output_echo.expected
+++ b/test/lwt/output_echo.expected
@@ -1,7 +1,8 @@
-listening on port 1235
-run echo client -p 1235 -n 10 --n-conn=2 -j=4
+run echo server on port=12346
+listening on port 12346
+run echo client -p 12346 -n 10 --n-conn=2 -j=4
 all done
-connecting to port 1235
+connecting to port 12346
 read: hello 1
 read: hello 1
 read: hello 1
diff --git a/test/lwt/output_hash.expected b/test/lwt/output_hash.expected
index c0b9551f..300672df 100644
--- a/test/lwt/output_hash.expected
+++ b/test/lwt/output_hash.expected
@@ -1,5 +1,7 @@
-listening on port 1234
-run hash client -p 1234 -d ../data/ --n-conn=2 -j=4
+running hash server on port=12345
+listening on port 12345
+listening on port=12345
+run hash client -p 12345 -d ../data/ --n-conn=2 -j=4
 ../data/d1/large: fdb479c5661572f9606266eeb280b4db5c26cc38
 ../data/d1/large: fdb479c5661572f9606266eeb280b4db5c26cc38
 ../data/d1/large_10: c31560efa1a5ad6dbf89990d51878f3bd64b13ce
@@ -440,5 +442,5 @@ run hash client -p 1234 -d ../data/ --n-conn=2 -j=4
 ../data/d9/large_9: 7893508ace6bc8a4d65e03ebf88a9be6c188af17
 ../data/d9/smol: 31416013d3060b8056a601c9f6719e94e7e9f7ed
 ../data/d9/smol: 31416013d3060b8056a601c9f6719e94e7e9f7ed
-connecting to port 1234
+connecting to port 12345
 hash dir="../data/"
diff --git a/test/lwt/run_echo.sh b/test/lwt/run_echo.sh
index de476edf..70d833e1 100755
--- a/test/lwt/run_echo.sh
+++ b/test/lwt/run_echo.sh
@@ -1,15 +1,16 @@
 #!/bin/bash
 
-PORT=1235
+PORT=12346
+echo "run echo server on port=$PORT"
 ./echo_server.exe -p $PORT &
 if [ "x$?" != x0 ]; then exit 1 ; fi
 
 
-sleep 0.9
-echo "run echo client -p $PORT $@"
+sleep 2
+echo "run echo client -p $PORT $*"
 
 export LC_LANG=C
 export LC_ALL=C
-./echo_client.exe -p $PORT $@ | sort
+./echo_client.exe -p $PORT "$@" | sort
 
 kill %1
diff --git a/test/lwt/run_hash.sh b/test/lwt/run_hash.sh
index 0adefd75..eca6cc57 100755
--- a/test/lwt/run_hash.sh
+++ b/test/lwt/run_hash.sh
@@ -1,10 +1,11 @@
 #!/bin/bash
 
-PORT=1234
+PORT=12345
+echo "running hash server on port=$PORT"
 ./hash_server.exe -p $PORT &
 if [ "x$?" != x0 ]; then exit 1 ; fi
 
-sleep 0.9
+sleep 2
 echo "run hash client -p $PORT $@"
 
 export LC_LANG=C