Hi Alin, On Thu, Oct 18, 2018 at 01:27:01PM +0200, Alin Nastac wrote: > From: Alin Nastac <alin.nastac@xxxxxxxxx> > > nf_conntrack_proto_generic refuse to handle grev6 packets when > NF_CT_PROTO_GRE is enabled, resulting in grev6 packets being > categorized as INVALID. IIRC, this depends on the pptp helper, right? I'm telling this because the PPTP helper is IPv4 only and in that case this will not help? Recent updates in nf-next removed the l3proto field. See: commit dd2934a95701576203b2f61e8ded4e4a2f9183ea Author: Florian Westphal <fw@xxxxxxxxx> Date: Mon Sep 17 12:02:54 2018 +0200 netfilter: conntrack: remove l3->l4 mapping information Which is part of what you want, right? Thanks.