Been using XCP-NG on our servers here at work for a few years now after moving off of hyper-v. We run exchange in house here, and in running the health checker script I noticed an error about the packets being discarded. I tried both the xcp and the citrix drivers but the result is the same. There are no NIC power management settings in any of the tabs and I did run the powershell command to disable nic power management just in case but the errors persist. I booted up one of the VMs on the old hyper V server as a test and it did not have these errors. The event lots also don’t have any useful info.
I also tested the MTU and it appears 1500 is correct (1472+28).