Index: head/sys/netinet6/ip6_output.c
===================================================================
--- head/sys/netinet6/ip6_output.c
+++ head/sys/netinet6/ip6_output.c
@@ -228,7 +228,20 @@
 			IP6STAT_INC(ip6s_odropped);
 			return (ENOBUFS);
 		}
-		m->m_flags = m0->m_flags & M_COPYFLAGS;
+
+		/*
+		 * Make sure the complete packet header gets copied
+		 * from the originating mbuf to the newly created
+		 * mbuf. This also ensures that existing firewall
+		 * classification(s), VLAN tags and so on get copied
+		 * to the resulting fragmented packet(s):
+		 */
+		if (m_dup_pkthdr(m, m0, M_NOWAIT) == 0) {
+			m_free(m);
+			IP6STAT_INC(ip6s_odropped);
+			return (ENOBUFS);
+		}
+
 		*mnext = m;
 		mnext = &m->m_nextpkt;
 		m->m_data += max_linkhdr;
@@ -253,8 +266,6 @@
 		}
 		m_cat(m, m_frgpart);
 		m->m_pkthdr.len = fraglen + hlen + sizeof(*ip6f);
-		m->m_pkthdr.fibnum = m0->m_pkthdr.fibnum;
-		m->m_pkthdr.rcvif = NULL;
 		ip6f->ip6f_reserved = 0;
 		ip6f->ip6f_ident = id;
 		ip6f->ip6f_nxt = nextproto;