I can't connect to my router's admin interface ?
Depending on your router's configuration, you might have to connect using a LAN port, and the client accessing the administration interface usually needs to be in the same IP range.
For example, if you need to connect to http://192.168.1.1 in order to access the management interface, your client PC needs to be in the range between 192.168.1.2/24 and 192.168.1.254/24.
There are a number of other troubleshooting steps you can take, here is a list:
Make sure you're using the correct IP address for the router, as well as the correct port (some use 8080 instead of the standard port 80). For a list of routers and their default IPs/passwords check our broadband hardware dataabse.
You can also often find your router's IP by simply typing: ipconfig in command prompt, and looking at the "Default Gateway" line.
Your client PC must be on the LAN side of the router (connected to a LAN port). You might want to try configuring it with a static IP address in the router's subnet (DHCP might not be configured properly yet).
Use a Cat5 cable to configure wireless routers - the wireless settings may not be configured correctly and wireless access to the admin interface may be disabled.
Reset the router to the factory defaults - they usually have a reset button, that when pressed for 10-30 seconds (while powering up) resets the router to the factory defaults, so you can login with the default password, etc. Note the procedure might be different for your particular router, check the user manual.
Disable web proxies - make sure Internet Explorer is not configured to use some type of web proxy for browsing.
Update firmware - sometimes a corrupt firmware can render the router useless. Try updating to the newest one from the manufacturer's website.
PING the router - In Command prompt, try: ping 192.168.0.1 (substitute with the actual IP of your router). If it works at least you have some connectivity to it and the cable is good.
DHCP ? - NAT routers usually act as DHCP servers to internal LAN clients. If you set your network adapter to "Obtain an IP address automatically" in the TCP/IP properties and your PC gets an internal IP address it is communicating with the router.
Check cables and LEDs are you getting the link LEDs on both ends of all cables? You might also try different Cat5 cables. The router has a number of LED indicators as well, power, connectivity to the WAN port, etc.
Telnet ? - some routers have a serial port where you can connect directly (using a serial cable) and manage the router's settings via telnet. Even though it's a text-based interface, it does not rely on the network/IPs at all.