Hello. I have an RUT955 running firmware 6.00.4
I have configured RS485 as a Modbus TCP gateway as per the picture below (on port 9502). I can poll the Modbus successfully from the mobile WAN port,or via the Wifi LAN, or through a openVPN tunnel across the mobile WAN.
I now set up a DMZ to one of the lan ports (10.143.1.50) where I have a second router. (my base lan address is 10.143.1.1) At this point I can no longer poll the Modbus for the mobile WAN. Although it will still work over VPN or from the LAN. I can repeat this fault and I have even tried reinstalling firmware and discarding existing settings to ensure the tables are clean.
One thing I have noticed is that a line appears in the Port Forwarding tab (on the webgui) when the DMZ and Remote Access (https) are both enabled. This entry in the port forwarding tab isn't visible all the time, as in you can refresh the page screen and it vanishes. The entry is called 'tlt_allow_remote_https_through_DMZ' and it forwards the remote port (9506 in my case) from the wan back to the LAN port 10.143.1.1
Taking this as a hint I constructed a similar rule to forward my port 9502 from the wan back to the lan 10.143.1.1, but this didn't work.
Any ideas please? For now I'm going to have to turn off the dmz and try constructing individual port forwarding rules.
Also I unsure about the Listening IP and the Allow IP fields on the RS485 tab, please can you elaborate, the wiki says very little.