i think i almost have the default pass, i have to understand one more function

verb/fs.sbin/vpn-passthru.sh

@@ -0,0 +1,35 @@
+#!/bin/sh
+
+. /sbin/config.sh
+. /sbin/global.sh
+
+l2tp_pt=`nvram_get 2860 l2tpPassThru`
+ipsec_pt=`nvram_get 2860 ipsecPassThru`
+pptp_pt=`nvram_get 2860 pptpPassThru`
+
+
+# note: they must be removed in order
+if [ "$CONFIG_NF_CONNTRACK_SUPPORT" = "y" ]; then
+	rmmod nf_nat_pptp 1>/dev/null 2>&1
+	rmmod nf_conntrack_pptp 1>/dev/null 2>&1
+	rmmod nf_nat_proto_gre 1>/dev/null 2>&1
+	rmmod nf_conntrack_proto_gre 1>/dev/null 2>&1
+else
+	rmmod ip_nat_pptp 1>/dev/null 2>&1
+	rmmod ip_conntrack_pptp 1>/dev/null 2>&1
+fi
+
+if [ "$pptp_pt" = "1" -o "$l2tp_pt" = "1" -o "$ipsec_pt" = "1" ]; then
+if [ "$CONFIG_NF_CONNTRACK_SUPPORT" = "y" ]; then
+	insmod -q nf_conntrack_proto_gre
+	insmod -q nf_nat_proto_gre
+
+	if [ "$pptp_pt" = "1" ]; then
+		insmod -q nf_conntrack_pptp
+		insmod -q nf_nat_pptp
+	fi
+else
+	insmod -q ip_conntrack_pptp
+	insmod -q ip_nat_pptp
+fi 
+fi