I have a cable modem connect to a router linksys. I can access my router linkys in local network by address 192.168.1.1. But I cannot access my router linksys by my public IP address. How can I do it? Can anyone help me? I have just come from another country. In my country we use adsl modem, when I from internet, I just type the public ip that I can login to my router
Some routers require that you turn on access via the public IP. Are you sure you've turned that on?
What model of Linksys router are you using? The exact steps to take may differ depending on what model of router you are using, but as 0siris mentioned, you will likely need to configure the router to allow management access to it from the Internet.
Linksys provides routers for home use and many such routers come with a default userid and password for management. For most users, allowing any system on the Local Area Network (LAN) side, i.e. from the 192.168.x.x private IP address space on the side of the router to which your computers connect, is not a security concern. However, by default, management access to the router from the Internet side is disabled. If it wasn't anyone in the world could potentially reconfigure your router if he knew the default userid and password for it. Since it is trivially easy to find such information online, e.g., one could simply check the manufacturer's website for the manual for the router, access from the Internet side is disabled by default. So you will need to reconfigure the router to allow such access. Before you do so, make sure you change the password to a strong password. If you don't, there are plenty of malicious individuals scanning systems on the Internet looking for vulnerable routers, computers, etc.