From a quick google search...
How to Perform a 30-30-30 Router Reset
Although any given router's procedure may differ, in general, the following steps tend to work on most brands of routers.
- With the router plugged in and powered on, depress the reset button for 30 seconds. This button is usually a tiny dot recessed into the back of the router. You may need a jeweler's screwdriver or a bent paperclip to access it.
- While still holding down the button, unplug the router from its power source for another 30 seconds.
- With the reset button still held down, turn the power back on and hold for another 30 seconds.
After this 90-second process is complete, your router is restored to its factory default state. Your particular router may not require the full 30-30-30 procedure. Some routers can be hard reset after only 10 seconds and without power cycling, but the 30-30-30 approach won't harm the router. Memorizing and following this 30-30-30 rule is recommended as a general guideline.
After a router has been reset, log in to it with the default IP address, username, and password that it was originally configured with. If your router is from one of the major router manufacturers such as
NETGEAR,
Linksys,
Cisco, or
D-Link, you'll find the default information for your router at their websites or in the documentation that came with the router.