diff --git a/netwerk/base/nsIOService.cpp b/netwerk/base/nsIOService.cpp
index d2f7c73d9..e76716d98 100644
--- a/netwerk/base/nsIOService.cpp
+++ b/netwerk/base/nsIOService.cpp
@@ -1182,7 +1182,7 @@ nsIOService::SetConnectivityInternal(bool aConnectivity)
 NS_IMETHODIMP
 nsIOService::AllowPort(int32_t inPort, const char *scheme, bool *_retval)
 {
-    int16_t port = inPort;
+    int32_t port = inPort;
     if (port == -1) {
         *_retval = true;
         return NS_OK;