diff --git a/src/shared/shared.go b/src/shared/shared.go
index 6b0d0b10c66d691f27da5a824d1ba082e7202826..e01a514609f2b6dfc1ba9776d9f91e3744f1ee4b 100644
--- a/src/shared/shared.go
+++ b/src/shared/shared.go
@@ -44,7 +44,7 @@ const NumFileReplicas = 4
 // How long to wait to get the membership list from the introducer
 const IntroducerTimeout = 3 * time.Second
 const GrepTimeout = 5 * time.Second
-const ACKTimeout = 1500 * time.Millisecond
+const ACKTimeout = 4000 * time.Millisecond
 const PingInterval = 3000 * time.Millisecond
 
 // Simulate false positives by dropping packets before they are sent out