Request for help: Debugging a slow connection between local devices in only one direction
I'm.... befuddled. Here's my setup:
- UniFi Security Gateway
- UniFi Switch Lite
- Two UAPs
- Two servers, A and B, connected to the USW-Lite with GbE
- Many wireless devices, connected to the UAPs
Here's what I'm experiencing:
- Network transfers from the wireless devices to server A (as measured by iperf3 tests) are very slow. Consistently between 10 and 20 Mb/s.
- Network transfers from server A to all devices are expected speeds. 900-1000 Mb/s to server B, 350-ish Mb/s to wireless devices.
- Network transfers between server B and all devices (in both directions!) are expected speeds.
- Network transfers from the USG to server A also seem slow, which is odd. Only about 60 MB/s.
- Network transfers from the USG to server B and the wireless devices is about 300 MB/s
So, specifically network transfers from any wireless device to server A are slow, and no other connections have any issues that I can see.
Some potentially relevant details:
- Server A is running Unraid
- Server B is running Ubuntu
- Wireless devices include a Fedora laptop, an iPhone, and a Macbook Pro
- UniFi configuration is pretty straightforward. I have a few ports forwarded, a guest WiFi network (that none of these devices are on), a single default VLAN, and two simple "Allow LAN" firewall rules for Wireguard on the USG. No other firewall or routing config that I'm aware of.
If anyone has any thoughts at all on how to continue debugging, I would be immensely grateful! I suppose the next step would be to try to determine whether it's the networking equipment or the server itself that is responsible for the throttling, but I'm not sure how best to do that.