Slow Internet Speed Sophos RED and Mikrotik

Hi members,

I need some help here. I am deploying sophos SD-WAN solution for a client but I faced with an issue that I can’t seem to find fix for. I am setting Sophos REDs on remote sites however, some of these devices have failed to communicate/provision to the central orchestration box due to some port negotiation issues with the ISP CPEs, so what I am doing is I intercept the traffic from ISP CPE with a mikrotik then connect the RED via DHCP from the Mikrotik then they are able to connect back to the central box.

Issue here is that when this happens, the internet speed is cut by up to 90% on the hosts however, a direct test from the ISP shows no speed cuts. I am trying to identify what could be cutting the internet speeds, I had someone mentioning a double NATing issue but can’t seem to find a way how to tackle this. For some other sites that are not having the mikrotiks, the speeds are fine so I wondering what could be going on in scenario where the mikrotik is being used to serve as DHCP server to the Sophos RED.

A far shot: if firewall rules (including mangle) are incompatible with fasttrack, user throughput drops to the floor. If you post mikrotiks’ config (text export), we might be able to help you better.