Hello everyone,
 

I'm currently facing a challenge with setting up a GRE tunnel on my network, and I'm hoping someone here might have some insights.
 

I have two servers running behind an Omada ER605 router, and I'm trying to establish a GRE tunnel from these servers to a VPS hosted on a different service provider. The GRE tunnel is successfully established, and ICMP pings are enabled on both ends.
 

However, there's no communication happening within the tunnel at all. The VPS (host) and the backend servers behind the ER605 cannot ping each other, and no data is being exchanged. The tunnel seems to be properly configured because it works without any issues when tested with servers outside LAN.
 

We've verified that ICMP pings are enabled, so that’s not the issue. The GRE tunnel is being created on the servers themselves, not using the router’s integrated tunneling options.
 

Given that the tunnel works fine with other servers outside the ER605 network, I suspect there might be a GRE passthrough setting or a similar configuration on the ER605 that needs to be enabled or adjusted. Unfortunately, I haven’t found any specific settings related to GRE passthrough in the router's management interface.
 

Has anyone experienced similar issues with the Omada ER605 or have any suggestions on what might be missing? Any advice would be greatly appreciated!
 

Thanks in advance for your help.