Usual recommendation is to run Asus Firmware on the Mesh Node and Merlin on the Main Router.
A Hard Reset is the best thing for stability when you make major firmware changes, then reenter your settings manually.
I use Transmission withAirVPN :
iptables -t nat -A PREROUTING -i tun+ -p udp --dport ***** -j DNAT --to-destination **.**.**.**
iptables -t nat -A PREROUTING -i tun+ -p tcp --dport ***** -j DNAT --to-destination **.**.**.**
Port test at open wi the Transmission GUI.
Put these statements in...
I do this with my VPN clients using CRON.
This should work for you with a modification from Client to Server.
Scheduled for 04:00.
In /jffs/scripts
#pasted into services-start script#
cru a vpnrst "0 4 * * * /jffs/scripts/VPN-Restart"
This creates the cron job and restores it after reboots...
I have no setup deviating from defaults in the asus router other than the FullCone. The passthroughs are all enabled and there is no port forwarding for voip..
I am using a linksys pap2 connected to Sipgate.