diff --git a/net/net.c b/net/net.c
index c96f566..313d5d8 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1390,7 +1390,7 @@
 		puts ("Got IP\n");
 #endif
 		if (len < IP_HDR_SIZE) {
-			debug ("len bad %d < %ld\n", len, IP_HDR_SIZE);
+			debug ("len bad %d < %lu\n", len, (ulong)IP_HDR_SIZE);
 			return;
 		}
 		if (len < ntohs(ip->ip_len)) {