Networking

Linux and Networking

Before explaining the powerful features Linux has to offer for networking computers, one must first understand the concepts of networking. This guide will teach you basic concepts of networking and how to apply them on your Linux machine. Linux and Networking

The Concepts of Networking

Linux supports numerous methods for networking. This includes serial communications, TCP/IP, and UUCP. Transmission Control Protocol/Internet Protocol (TCP/IP) has become the most successful mechanism for networking computers around the world. TCP/IP is a set of protocols that define how machines should communicate with each other through a network. On a TCP/IP network, each machine is assigned an IP address, a 32-bit number uniquely identifying the machine. An example IP address would be 192.168.0.1, usually four numbers separated by dots. The IP address is divided into two parts, the network address and the host address. The network address is the first two parts and the host address is the last two parts. In the example above, the network address would be 192.168, and 0.1 would be the host address. The IP address is important because it is used to route data from one machine to another. TCP transmits and receives data in units known as packets. Packets contain portions of information to send to another machine, as well as a header specifying the destination and source port addresses. Internet Protocol (IP) is responsible for transmitting and routing the TCP packets through the network. This is where the IP address comes in.

The network is set up with client workstations logging on to a network server. The server uses a gateway to connect to other networks. Look at the diagram below to understand how a network works.

Networking with Linux

Now that the concepts of networking are clear, this guide will now move on to setting up a network on Linux (which, hopefully, shouldn't be too hard!) The guide serves only to point you in the right direction. Should trouble arise, contact your network administrator or consult the man pages. If you are the network administrator, consult the man pages or go to our links section and see some troubleshooting sites. The guide assumes that TCP/IP support (which includes Telnet, FTP, system-administration commands, and network configuration files) has been installed on your workstation and that you have an Ethernet device installed on your computer.

The generic way of configuring a network on Linux is to edit the rc files. The rc files needed for network configurations are usually located in the directory /etc/rc.d. Many versions of Linux have their own separate way of configuring a network. For example, Red Hat provides a control panel editor that configures the network automatically, bypassing the use of the rc files. The files you need to edit are rc.inet.1 and rc.inet2. rc.inet1 is used to configure network device interface with certain parameters. rc.inet2 is used to run various daemons used by TCP/IP. A daemon is a Unix term for a process that runs in the background all the time. A lot of daemons are used to handle network activity. Configure the files so that the settings are correct on your computer. If you run into any problems, consult the man pages. The best way to configure a network on your system would be to use the tools that your particular distribution offers you. Most distributions like Red Hat and SuSE have tools that can make installing a network a lot easier. Unless you're feeling bold and courageous, refer to your distribution manual to find out more about networking your system. Should you desire to connect Windows workstations to your Linux box, you need to install NFS (Network File System). NFS allows you to access files as if they were stored on your local disk. Consult your distribution manual for the configuration of NFS or refer to a HOWTO. Once your network is complete, you will be able to utilize Linux's most powerful tool.