Brume 2 – LAN Port Stuck at 100 Mbps, Causing VPN Speed Bottlenecks (Tried Everything)

Technical Support for Routers VPN, DNS, Leaks
1

Hi all,

I’m using the GL-MT2500 (Brume 2) as a WireGuard VPN server, and I’m hitting a frustrating bottleneck — the LAN port refuses to negotiate above 100 Mbps, and it’s crippling my VPN throughput.

Setup:
• Router: Virgin Media Hub 5 (model: F3896LG-VMB)
• Brume 2 WAN: 2.5 Gbps port plugged into Hub — working fine.
• Brume 2 LAN: Connected to client device (MacBook Pro) — stuck at 100 Mbps full duplex.
• Firmware: Latest OpenWRT snapshot preinstalled (21.02-SNAPSHOT)

What I’ve Tried:
• Multiple Ethernet cables (including the one GL.iNet shipped)
• Switching router ports (tried all 4, avoiding QoS Port 1)
• Ran ethtool -s eth1 speed 1000 duplex full autoneg off → Brume 2 crashes/disconnects from SSH
• Confirmed eth1 still shows 100 Mbps even after reboot
• Brume is set to VPN Server only, no Client VPN enabled
• Tested internet speed with WireGuard enabled:
~11 Mbps down / 6 Mbps up, ping 73 ms

Other Notes:
• WAN port correctly negotiates 2.5 Gbps full duplex (eth0)
• LAN port (eth1) is the bottleneck — even though my device is connected via the WAN port (acting as router uplink), the client device uses the LAN
• I’ve confirmed via UI that LAN is still capped:
Network Port Management → LAN = 100 Mbps full duplex

I’ve seen other users report the same thing in various forums — is this a known hardware/software limitation? Or something I can resolve via config or patch?

Any help would be greatly appreciated. I’m willing to provide logs or SSH access if needed.

2

Hi,

  1. If the MacBook Pro is connected to another router/switch, does it NIC port rate reach 1000Mbps? Or if the LAN port of Brume 2 is connected to other client devices, does the LAN port rate reach 1000Mbps?

  2. Please SSH to the router, and execute the command: ethtool eth1 to check "Advertised link modes" and "Link partner advertised link modes".

  3. What test did this networking speed pass? from "speedtest.net" or copy/read files via VPN?

  1. What is the Internet DL/UL rate of your main router/ISP modem?