base-files: enable option to skip the netfilter "filter" table for established connection packets by default

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

Backport of r42048

git-svn-id: svn://svn.openwrt.org/openwrt/branches/barrier_breaker@42051 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/base-files/files/etc/sysctl.conf

@@ -21,6 +21,7 @@ net.netfilter.nf_conntrack_max=16384
 net.netfilter.nf_conntrack_tcp_timeout_established=7440
 net.netfilter.nf_conntrack_udp_timeout=60
 net.netfilter.nf_conntrack_udp_timeout_stream=180
+net.netfilter.nf_conntrack_skip_filter=1
 
 # disable bridge firewalling by default
 net.bridge.bridge-nf-call-arptables=0