I’m having a strange Ethernet problem on Windows and I’m running out of ideas.

My Wi-Fi works perfectly, but Ethernet does not get a proper IP address.

Hardware / network

• Ethernet adapter: Realtek Gaming 2.5GbE Family Controller
• Windows detects Ethernet as Connected
• Adapter status: Up
• Link speed: 1 Gbps
• Wi-Fi works normally
• Router/network appears to use 192.168.68.x
• Router/default gateway on Wi-Fi: 192.168.68.1
• Wi-Fi gets an address such as 192.168.68.61

Ethernet problem

Originally Ethernet was getting:

169.254.17.201

with:

255.255.0.0

and no normal IPv4 default gateway.

Running:

ipconfig /renew "Ethernet"

gave:

Unable to contact your DHCP server. Request has timed out.

So it looks like Windows sees the Ethernet link, negotiates at 1 Gbps, but cannot get a DHCP lease.

Things I've tried

Network stack reset:

ipconfig /flushdns

ipconfig /release

ipconfig /renew

netsh winsock reset

netsh int ip reset

Restarted the PC afterward.

I also tried disabling/enabling the Ethernet adapter and restarting it through PowerShell.

Checked:

Get-NetAdapter -Name Ethernet

Result:

• Status: Up
• LinkSpeed: 1 Gbps
• InterfaceDescription: Realtek Gaming 2.5GbE Family Controller

Checked:

Get-NetIPInterface -InterfaceAlias "Ethernet" -AddressFamily IPv4

DHCP was enabled during the original problem, but DHCP requests still timed out.

Realtek advanced settings

I checked all the advanced Realtek properties.

Some of the settings included:

• Flow Control: Rx & Tx Enabled
• Interrupt Moderation: Enabled
• IPv4 Checksum Offload: Rx & Tx Enabled
• Jumbo Frame: Disabled
• Large Send Offload IPv4/IPv6: Enabled
• ARP Offload: Enabled
• NS Offload: Enabled
• Receive Buffers: 512
• Speed & Duplex was set to 1.0 Gbps Full Duplex
• Priority & VLAN was enabled
• VLAN ID: 0
• TCP/UDP checksum offloads enabled

I changed Speed & Duplex back to Auto Negotiation.

I also tried disabling Priority/VLAN. The Realtek driver uses the option:

Priority & VLAN Disabled

rather than simply Disabled.

Static IP test

I temporarily assigned Ethernet:

• IP: 192.168.68.200
• Prefix: /24
• Gateway: 192.168.68.1
• DNS: 1.1.1.1 and 8.8.8.8

At one point Windows showed the static 192.168.68.200 configuration correctly.

I later removed the static configuration to go back to DHCP.

After returning to automatic addressing, Ethernet went straight back to:

169.254.17.201

Ping tests

With Wi-Fi disabled, Ethernet cannot reach:

ping 192.168.68.1

ping 8.8.8.8

ping google.com

At one point pinging 192.168.68.1 returned:

PING: transmit failed. General failure.

rather than just a normal request timeout.

Physical power reset

I have also:

• Completely shut down the PC
• Unplugged it from power
• Unplugged Ethernet
• Held the power button while unplugged
• Left it without power for a few minutes
• Reconnected everything and booted again

I tried this because a similar full power drain fixed a Bluetooth hardware issue for me before.

It did not fix the Ethernet issue.

Current DHCP situation

While troubleshooting the static IP settings, I noticed DHCP eventually showed as Disabled on the Ethernet IPv4 interface.

I have now turned it back on using:

Set-NetIPInterface -InterfaceAlias "Ethernet" -AddressFamily IPv4 -Dhcp Enabled

and reset DNS to automatic with:

Set-DnsClientServerAddress -InterfaceAlias "Ethernet" -ResetServerAddresses

So DHCP being disabled at the end was caused during troubleshooting and was not the original issue. Originally DHCP was enabled and still timed out.

What confuses me

The Realtek adapter:

• Is detected correctly
• Says Connected
• Is Up
• Negotiates a 1 Gbps physical link
• Has DHCP enabled
• But originally could not contact the DHCP server
• Falls back to 169.254.x.x
• Cannot reach 192.168.68.1 over Ethernet
• Wi-Fi on the same PC/router works normally

I’m wondering if this is:

• A corrupted Realtek driver
• A Realtek registry/advanced-property issue
• Broken Windows network bindings
• Router/LAN port issue despite successful 1 Gbps negotiation
• Cable issue despite the 1 Gbps link
• Some VLAN/offload setting
• Something else entirely

My next thought is doing a completely clean uninstall/reinstall of the Realtek Gaming 2.5GbE Family Controller driver.

Has anyone seen a Realtek 2.5GbE adapter negotiate a normal 1 Gbps link but still completely fail DHCP/network traffic like this? What would you check next?