--- xtables-addons-2.13/extensions/xt_DNETMAP.c~	2017-06-29 14:46:37.000000000 +0200
+++ xtables-addons-2.13/extensions/xt_DNETMAP.c	2017-11-16 10:15:47.371793222 +0100
@@ -377,9 +377,9 @@
 	unsigned int hooknum = par->hooknum;
 #endif
 
-	NF_CT_ASSERT(hooknum == NF_INET_POST_ROUTING ||
+	WARN_ON(!(hooknum == NF_INET_POST_ROUTING ||
 		     hooknum == NF_INET_LOCAL_OUT ||
-		     hooknum == NF_INET_PRE_ROUTING);
+		     hooknum == NF_INET_PRE_ROUTING));
 	ct = nf_ct_get(skb, &ctinfo);
 
 	jttl = tginfo->flags & XT_DNETMAP_TTL ? tginfo->ttl * HZ : jtimeout;