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.
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?
Please SSH to the router, and execute the command: ethtool eth1 to check "Advertised link modes" and "Link partner advertised link modes".
What test did this networking speed pass? from "speedtest.net" or copy/read files via VPN?
What is the Internet DL/UL rate of your main router/ISP modem?
MacBook Pro NIC Port Rate: Yes — when connected to other routers and switches, my MacBook Pro consistently negotiates at 1000 Mbps full duplex without issue.
Brume 2 LAN Behavior on Other Devices: When the Brume 2’s LAN port is connected to other client devices (tested with two laptops and a desktop), it still negotiates at only 100 Mbps full duplex.
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Link partner advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Speed: 100Mb/s
Duplex: Full
As shown, the Brume 2 is not advertising 1000 Mbps at all, which strongly suggests a hardware or PHY-level fault on eth1.
4. Speed Testing Method:
VPN speed was measured using:
• Speedtest.net (via iPhone over WiFi connected to Brume 2)
• Direct iperf3 tests showed similar performance degradation.
• Internet DL/UL speed at the ISP router (Virgin Media Hub 5) is 500 Mbps down / 50 Mbps up. WireGuard server on Brume 2 was the only limiting factor.
To summarise, the WAN port negotiates at 2.5 Gbps, but the LAN port is locked at 100 Mbps regardless of device, cable, or port.
I’ve already performed:
• Cable swaps (CAT6 & CAT7)
• Port swaps on router
• Uboot reflash with settings wiped
• Manual ethtool overrides (crashes SSH without resolving)
At this point, I’ve already been approved for a replacement via support (Ticket: 72188:1458212) and have provided my order number and MAC address.
Please confirm there are no further tests required so I can proceed with returning the device.
