Hi All,

I have 2 x ISP modems connected to TP-Link ER605 Router with Load Balancing feature checked, and everything else is connected to a TP-Link Jetstream switch and I am having trouble connecting to my Synology Nas with DDNS.

Here is my configuration and what I have done so far :)

From the Omada Controller (Settings/Transmission/Nat/Port Forwarding), I forward port 5000-5001 and the Interface is set to both Wan1 and Wan2. 

Both ISP modems’ DMZ is turned on. (One of them is VDSL Archer VR600, Other is 4,5G Huawei B525s)

With this configuration setup, when I try to test the connections from Synology's Route Configuration, sometimes I get OK from port 5000, and sometimes from 5001. Never both test results come OK. 

When I tried to turn off the Wan1, then all test results Failed. When I turn off the Wan2, then all test results are OK.

If I enable the Link Backup mode On from the Omada Controller, all the results are fine, but I need both my ISP to run simultaneously. 

Is there any way to make Synology's IP address access to the internet only from Wan1? Only other clients use the both Wan, only Synology use Wan1? If I can manage to do that, I believe I will solve the problem?

I am fully lost here and tried almost everything :) Any help would be appreciated...

Best...