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Securing-Optimizing-RH-Linux-1_2_94
Comments and suggestions concerning this book should be mailed to gmourani@videotron.ca © Copyright 1999-2000 Gerhard Mourani and Open Network Architecture ® 94 Linux TCP/IP Network Management Overview As far as now, we are not playing with the networking capabilities of Linux. Linux is one of the best existing operating system in this world for his networking features. Most Internet site around the world already knows this and use it since long time. Understanding your hardware network and all files related to it is very important if you want to have a full control of what happen in your server. Good knowledge of primary networking commands is vital. Network management covers a wide variety of topics. In general it includes gathering statistical data and status information about parts of your network, and taking action as necessary to deal with failures and other changes. The most primitive technique for network monitoring is periodic "pinging" of critical hosts. More sophisticated network monitoring requires the ability to get specific status and statistical information from various devices on the network. These should include various sorts of data gram counts, as well as counts of errors of various kinds. For these reasons, in this chapter we will try to answer fundamental questions about networking devices, files related to networking functionality, and essential networking commands. Install more than one Ethernet Card per Machine You might use Linux as a gateway between two Ethernet networks. In that case, you might have two Ethernet cards on your server. To eliminate problems at boot time, the Linux kernel doesn’t detect multiple cards automatically. If you happen to have two or more cards, you should specify the parameters of the cards on the “lilo.conf” file for a monolithic kernel or on the conf.modules”  file for a modularized kernel. The following are problems you may encounter with your network cards. Problem 1 If the driver(s) of the card(s) is/are being used as a loadable module (modularized kernel), in the case of PCI drivers, the module will typically detect all of the installed cards automatically. For ISA cards, you need to supply the I/O base address of the card so the module knows where to look. This information is stored in the file “/etc/conf.modules”. As an example, consider we have two ISA 3c509 cards, one at I/O 0x300 and one at I/O 0x320. For ISA cards, edit the  conf.modules file (vi /etc/conf.modules) and add: alias eth0 3c509 alias eth1 3c509 options 3c509 io=0x300,0x320 This says that the 3c509 driver should be loaded for either eth0 or eth1 (alias eth0, eth1) and it should be loaded with the options io=0x300,0x320 so that the drivers knows where to look for the cards. Note that 0x is important – things like 300h as commonly used in the DOS world won’t work. For PCI cards, you typically only need the alias lines to correlate the ethN interfaces with the appropriate driver name, since the I/O base of a PCI card can be safety detected. For PCI cards, edit the  conf.modules file (vi /etc/conf.modules) and add: alias eth0 3c509 alias eth1 3c509