One of the most common problems that many Internet users face is a sudden change of their default gateway from the typical 192.168.0.1 to an IP address that starts with fe80. This is a very common problem and it usually occurs after you reboot the router or modem provided by your internet/cable company. It can be very confusing as to why there is this sudden change of the default gateway and how it impacts your internet connection.
Why Is My Default Gateway FE80?
Typically what happens is that sometimes when you reboot your router, it reverts into a modem-only operation. Many of the routers have an IPv4 IP address. However, when you reboot the router it sometimes gets the more recent IPv6 address. The IP or Internet Protocol provides identification and acts as a location system for computers on different networks. These IP addresses route the traffic across the Internet. Now when your router gets an IPv6 address, there is a possibility that it can get another address type that is different from the IPv4 address. It is known as the link-local address. Usually, the link-local iPv6 addresses carry the FE80. It is a hexadecimal representation of the first 10 bits of 128-bit IPv8 address.
So when a host boots his device, the device automatically gets assigned with the FE80 IPv6 address to the interface. The format of such a link-local address is given below.
FE80 : 0000 : 0000 : 0000 : abcd : abcd : abcd : abcd
So it is actually nothing to worry about. It is the normal behavior expected from the cable modems. In such a scenario what you have to do is to try and revert the router from only performing the modem-only operation back to the full router or consumer gateway.
The ipconfig output of your internet will show that you are directly connected with an external network. What this means is that you have a public IP address through DHCP. This is directly from the network of your internet service provider and not from your router. In such a scenario, users are often not able to swap their devices. This is because most of the cable operators limit their modems to a single DHCP lease only.
If you encounter such a problem there are a number of things that you can try. Firstly what you need to do is to check the documentation provided by your ISP in order to see if there is a documented method given to switch your router’s operation mode form modem only to the full router or consumer gateway operation. If you are unable to find such documentation then what you can try is resetting the modem using the pinhole reset.
As a last case effort to change your default gateway from FE80 to the usual 192.168.0.1, you will have to contact your Internet service provider. They will be able to re-flash your modem and the correct operation along with the correct IP address will be restored. Also, your ISP will be able to guide you through the process of solving any other issues that might be causing the change of your default gateway.