Troubleshoot Internet Connection

1. Make sure you can connect to your router by ping to your router IP (for example: 192.168.1.1) from command line (Windows) or terminal (Mac or Linux) or access to the router web page using the browser. If you cannot ping or see the router web page, check your network configuration on your computer.
2. Are you using the wireless? If yes, connect the CAT 5 Ethernet cable connect to your computer.
3. Is the wired connection working? If yes, your wireless has issue.
4. If the wired connection is not working, is other computer in your home, your office or your LAN can access to the Internet? If just only your computer, check your network configuration.
5. If all computers in your LAN could not access to the Internet, power down both the router and cable modem.
6. Wait for 15 seconds, and turn them on.
7. If you still not connect, check to see there is outage in your area. If not, verify your router is working.
8. To verify your router is in good condition, hook up another spare router or your computer directly to the cable modem. Note: If you hook up your computer directly to the cable modem, make sure the firewall on computer enable and all ports other than 80 are closed. Connect computer with open ports: 20, 21, 139, 3389 directly to cable modem or Internet is dangerous and not recommend. Here, I'm using my test computer running GNU Linux with all closed ports to connect directly to the router.
9. If you can connect to the Internet without router or with another router for an hour or more, your existing router is bad. It need a replacement.
10. If you cannot connect to the internet, chance is your cable modem or the link from cable modem to your internet service provider have issue, call your internet service provide technical support.