Welcome to Linux Knowledge Base and Tutorial
"The place where you learn linux"
The ONE Campaign to make poverty history

 Create an AccountHome | Submit News | Your Account  

Tutorial Menu
Linux Tutorial Home
Table of Contents
Up to --> System Monitoring

· Finding Out About Your System
· Hardware and the Kernel
· Terminals
· Hard Disks and File Systems
· User Files
· Network Files
· Important System Files

Glossary
MoreInfo
Man Pages
Linux Topics
Test Your Knowledge

Site Menu
Site Map
FAQ
Copyright Info
Terms of Use
Privacy Info
Disclaimer
WorkBoard
Thanks
Donations
Advertising
Masthead / Impressum
Your Account

Communication
Feedback
Forums
Private Messages
Recommend Us
Surveys

Features
HOWTOs
News
News Archive
Submit News
Topics
User Articles
Web Links

Google
Google


The Web
linux-tutorial.info

Who's Online
There are currently, 296 guest(s) and 3 member(s) that are online.

You are an Anonymous user. You can register for free by clicking here

  
Linux Tutorial - System Monitoring - Finding Out About Your System - Network Files
  User Files ---- Important System Files  


Network Files

If you are running TCP/IP, you can look in a couple of places for information about your system. First, check out the file /etc/resolv.conf. If you don't find it and you know you are running TCP/IP, don't worry! The fact that it is missing tells you that you are not running a nameserver in your network. If it is not there, you can find a list of machines that your machine knows about and can contact by name in /etc/hosts. If you are running a nameserver, this information is kept on the nameserver itself.

The content of the /etc/hosts file is the IP address of a system followed by its fully qualified name, and then any aliases you might want to use. A common alias simply uses the node name and omits the domain name. Each line in the /etc/resolv.conf file contains one of a couple different types of entries. The two most common entries are the domain entry, which is set to the local domain name, and the nameserver, which is followed by the IP address of the name "resolver." See the section on TCP/IP for more information on both of these files.

It's possible that your machine is the nameserver itself. To find this out, look at the file /etc/named.conf. If this exists, it is probably a nameserver. The /etc/named.conf file will tell you the directory where the name server database information is kept. For information about the meaning of these entries, check out the named man-page, as well as the section on TCP/IP.

Another place to look is the start-up scripts in /etc/rc.d. Often, static routes are added there. One likely place is /etc/rc.d/init.d/network. If these static routes use tokens from either /etc/networks or /etc/gateways that are incorrect, then the routes will be incorrect. By using the -f option to the route command, you can flush all of the entries and start over.

Although not as often corrupted or otherwise goofed up, a couple other files require a quick peek. If you think back to our telephone switchboard analogy for TCP, you can think of the /etc/services file as the phone book that the operator uses to match names to phone numbers. Rather than names and phone numbers, /etc/services matches the service requested to the appropriate port. To determine the characteristics of the connection, inetd uses /etc/inetd.conf, which contains such information as whether to wait for the first process to finish before allowing new connections.

Other common places for confusion are incorrect entries and the inevitable calls to support deals with user equivalence. As I talked about in the section on TCP/IP, when user equivalence is set up between machines, many remote commands can be executed without the user having to produce a password. One more common misconception is the universality of the /etc/hosts.equiv file. Though this file determines what user equivalence should be established with what other machine, it does not apply to one user: root. To me, this is rightly so. Though it does annoy administrators who are not aware of this, it is nothing compared to the problems that might occur if it did apply to root, and this is not what you would expect.

To allow root access, you need to create a .rhosts file in roots home directory (usually /) that contains the same information as /etc/hosts.equiv but instead applies to the root account. The most common mistake made with this file is the permission. If the permission is such that any user other than root (as the owner of the file) can read it, the user-equivalent mechanism will fail. See /etc/hosts.equiv and $HOME/.rhosts to see which remote users have access to which user accounts.

A list of the essential system files can be found here.

 Previous Page
User Files
  Back to Top
Table of Contents
Next Page 
Important System Files


MoreInfo

Test Your Knowledge

User Comments:


You can only add comments if you are logged in.

Copyright 2002-2009 by James Mohr. Licensed under modified GNU Free Documentation License (Portions of this material originally published by Prentice Hall, Pearson Education, Inc). See here for details. All rights reserved.
  




Login
Nickname

Password

Security Code
Security Code
Type Security Code


Don't have an account yet? You can create one. As a registered user you have some advantages like theme manager, comments configuration and post comments with your name.

Help if you can!


Amazon Wish List

Did You Know?
You can get all the latest Site and Linux news by checking out our news page.


Friends



Tell a Friend About Us

Bookmark and Share



Web site powered by PHP-Nuke

Is this information useful? At the very least you can help by spreading the word to your favorite newsgroups, mailing lists and forums.
All logos and trademarks in this site are property of their respective owner. The comments are property of their posters. Articles are the property of their respective owners. Unless otherwise stated in the body of the article, article content (C) 1994-2013 by James Mohr. All rights reserved. The stylized page/paper, as well as the terms "The Linux Tutorial", "The Linux Server Tutorial", "The Linux Knowledge Base and Tutorial" and "The place where you learn Linux" are service marks of James Mohr. All rights reserved.
The Linux Knowledge Base and Tutorial may contain links to sites on the Internet, which are owned and operated by third parties. The Linux Tutorial is not responsible for the content of any such third-party site. By viewing/utilizing this web site, you have agreed to our disclaimer, terms of use and privacy policy. Use of automated download software ("harvesters") such as wget, httrack, etc. causes the site to quickly exceed its bandwidth limitation and are therefore expressly prohibited. For more details on this, take a look here

PHP-Nuke Copyright © 2004 by Francisco Burzi. This is free software, and you may redistribute it under the GPL. PHP-Nuke comes with absolutely no warranty, for details, see the license.
Page Generation: 0.11 Seconds