diff --git a/src/proxy/tinymitm/proxy.cpp b/src/proxy/tinymitm/proxy.cpp
index 18c9a6f..2016b68 100644
--- a/src/proxy/tinymitm/proxy.cpp
+++ b/src/proxy/tinymitm/proxy.cpp
@@ -103,13 +103,18 @@ struct HttpStream
 /*
     platform specific stuff
 */
-void setNonBlocking(SOCKET s)
+void setNonBlocking(SOCKET s, bool enabled)
 {
 #ifdef _WIN32
-    unsigned long mode = 1;
+    unsigned long mode = enabled ? 1 : 0;
     ioctlsocket(s, FIONBIO, &mode);
 #else
-    fcntl(s, F_SETFL, fcntl(s, F_GETFL, 0) | O_NONBLOCK);
+    int flags = fcntl(s, F_GETFL, 0);
+    if (enabled)
+        flags |= O_NONBLOCK;
+    else
+        flags &= ~O_NONBLOCK;
+    fcntl(s, F_SETFL, flags);
 #endif
 }