| The Linux Documentation Project at http://www.tldp.org/ offers many in-depth resources for configuring and troubleshooting these connections. The Internet search engine Google is also an invaluable tool for dealing with specific questions about these connections. For many other useful references, see the "Reference" section at the end of this chapter. Here are a few troubleshooting tips culled from many years of experience: If your modem connects and then hangs up, you are probably using the wrong password or dialing the wrong number. If the password and phone number are correct, it is likely an authentication protocol problem. If you get connected but cannot reach websites, it is likely a domain name resolver problem, meaning that DNS is not working. If it worked yesterday and you haven't "adjusted" the associated files, it is probably a problem at the ISP's end. Call and ask. Always make certain that everything is plugged in. Check againand again. If the modem works in Windows, but not in Linux no matter what you do, it is probably a software modem no matter what it said on the box. If everything just stops working (and you do not see smoke), it is probably a glitch at the ISP or the telephone company. Take a break and give them some time to fix it. Never configure a network connection when you have had too little sleep or too much caffeine; you will just have to redo it tomorrow.
Related Ubuntu and Linux Commands You will use these commands when managing network connectivity in your Ubuntu system: dhclient Automatically acquire, and then set IP info for a NIC ethereal GNOME graphical network scanner firestarter Ubuntu's basic graphical firewalling tool for X ifconfig Displays and manages Linux networking devices iwconfig Displays and sets wireless network device parameters route Displays and manages Linux kernel routing table ssh The OpenSSH remote-login client and preferred replacement for telnet network-admin Ubuntu's GUI for configuring network connections
|
Using Patches/Upgrades to Keep Your Network Secure One of the keys to security not mentioned previously is to keep up-to-date with at least the latest stable versions of your software. Each time a new version of a software package comes out, it corrects any known security holes found in the previous release. Also be sure to keep your operating systems patched to the latest patch level. Your network security is only as strong as the weakest host. Refer to Chapter 7, "Managing Software," for details on how to use apt-get to update Ubuntu with newer software packages. See Chapter 35, "Kernel and Module Management," to see how to update your Linux kernel. With effort, your system can be secure enough to keep most intruders out. Just keep your software up-to-date and keep yourself informed of potential security threats to your software, and you should be fine. |
