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My laptop's NIC went bad and I had to start using a USB Ethernet adapter. When I start up the computer, or even simply unplug and plug in the adapter, it gets two default gateways which show up in ipconfig: the router's IP address and 0.0.0.0.

Looking into this more, I did a route print and this showed up:

0.0.0.0  0.0.0.0  On-link  192.168.0.5  20
0.0.0.0  0.0.0.0  192.168.0.1  192.168.0.5  20

Searching the internet results in the majority of the blame being a service called "Bonjour" but I don't have that on my system.

If I can't find the root cause of the incorrect route, is there a way to change the metric for that 0.0.0.0 on-link route so it doesn't get used? I am new to Windows routing tables and I would like this to be persistent and I don't want to have to change things every time I connect to a different network.

Right now, my temporary solution is to run a command prompt and type in the following command, but I have to edit the gateway for every network I connect to. I also have to run this after every reboot, sleep, or disconnect of the USB Ethernet adapter.

route change 0.0.0.0 MASK 0.0.0.0 192.168.0.1

After more troubleshooting, I see the route to 0.0.0.0 default gateway being added when it gets the automatic private IP. It seems to assign itself a 169 address and 0.0.0.0 gateway too fast, before it gets the DHCP response and information.

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2 Answers 2

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0.0.0.0 is the default route (the route used if there are no specific rues to affect the current traffic packet).

On-link as the gateway means that the route resolves locally.

The default route resolving locally may be happening due to installed network security software setting it to redirect traffic through its scanning engines.

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  • There is no security software other than Microsoft Security Essentials and Windows Firewall. The issue only happens on the USB Ethernet adapter and does not happen on the wireless connection.
    – Syntax42
    Jan 22, 2014 at 17:40
  • It could simply be the way that USB adapter works as well. It may be routing traffic locally to pass it through the USB drivers. Hard to say without additional troubleshooting done to the system. Jan 22, 2014 at 17:44
  • With the 0.0.0.0 default gateway, it can't connect to anything beyond the LAN. That's why I have to change the route manually every time. I'm looking for something more permanent that fixes the route showing up or sets it to the lowest priority.
    – Syntax42
    Jan 22, 2014 at 17:54
  • I'd suggest editing your original question and add the fact that it prevents you from surfing, as well as what you currently do to 'fix' it. Providing information such as that will help get you better answers. Jan 22, 2014 at 18:03
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Maybe you need to disable the built-in NIC in the bios, or disable the driver for it (you didn't specify what OS you are using).

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  • This is running on Windows. I have tried drivers from the manufacturer and the automatic drivers downloaded by Windows from Windows Update.
    – Syntax42
    Jan 22, 2014 at 17:39
  • The OS isn't so much relevant in what I'm trying to communicate. I'm saying if you have a funky-acting internal NIC, you may get weird results with route print as long as it is still enabled, because the operating system will still see the internal nic. So try disabling the internal NIC, either in Device Manager, or in the BIOS.
    – Xavier J
    Jan 22, 2014 at 17:42
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    This doesn't make sense to me. I can try it, but I doubt it will make a difference. When a NIC isn't connected, it has no IP address. Without an IP address, no route will be generated for it.
    – Syntax42
    Jan 22, 2014 at 17:52

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