diff --git a/src/i_tcp.c b/src/i_tcp.c
index 89e59c8b8..eca218c80 100644
--- a/src/i_tcp.c
+++ b/src/i_tcp.c
@@ -466,7 +466,7 @@ static boolean SOCK_cmpaddr(mysockaddr_t *a, mysockaddr_t *b, UINT8 mask)
 	UINT32 bitmask = INADDR_NONE;
 
 	if (mask && mask < 32)
-		bitmask = htonl(-1 << (32 - mask));
+		bitmask = htonl((UINT32)(-1) << (32 - mask));
 
 	if (b->any.sa_family == AF_INET)
 		return (a->ip4.sin_addr.s_addr & bitmask) == (b->ip4.sin_addr.s_addr & bitmask)