Linux is growing. It is now used in many everyday gadgets such as cell phones, PDAs, MP3 players, TVs, printers, portable GPS systems and cameras. It's no longer just for systems administrators. Join the wave! This site covers topics needed for Linux software certification exams, such as the RHCE, and many computer training courses.

Chapter 14 - Linux Firewalls Using iptables: Security is an essential part of Web life. This chapter gives an explanation of the most popular Linux based firewall software with a step-by-step examples of a script/program you can write to protect your network.

Chapter 15 - Linux FTP Server Setup: Shows how to set up a Linux server to allow uploading and downloading of files from the Internet using the File Transfer Protocol (FTP) package. FTP can be tricky to configure with firewalls and a sample iptables script is provided. There is also a tutorial on how to set up an FTP server to allow people to download only, not upload files for the sake of security.

Chapter 16 - Telnet, TFTP and xinetd: Coverage of how to log into a Linux server from a remote PC using the commonly available Telnet program. Also offers an example of how to save the configuration files of various Cisco networking devices to a Linux server using TFTP. Both the Telnet and TFTP packages are governed by the xinetd program which is also explained.

Chapter 17 - Secure Remote Logins and File Copying: Telnet is very insecure as the data passing between the client and server is unencrypted. This chapter covers how to setup a secure shell (SSH) server for encrypted communications as an alternative to Telnet. Also covers how to configure SSH to allow you to both log in to a remote Linux server without a password and to execute commands on a remote Linux server on demand.

Chapter 18 - Configuring DNS: How to configure the Domain Name Services (DNS) on a Linux server that will enable you to map an Internet address to a Web site name. Explains the different types of DNS servers and discusses simple methods of how to make them serve your departmental network.

Chapter 19 - Dynamic DNS: In many cases you might want to host a Web site on a DSL line. Regular DNS relies on an Internet network whose Internet address doesn't change. Many home and office networks get their Internet addresses dynamically assigned. This chapter covers how to track this constant change so that your Web site's name (URL) always points to your new Internet address.

Chapter 20 - The Apache Web Server: Once DNS is configured you need to set up a server to handle your Web site's pages. The Apache Web server package is the most commonly used Linux software used for this task, but the configuration file can be difficult to understand. This chapter explains how to create a Web site simply by tacking on easy-to-understand customizations to the end of the configuration file. Full examples provided.

Chapter 21 - Configuring Linux Mail Servers: Covers how to configure the sendmail mail server to manage mail for your Web site. sendmail can be difficult to configure, but it can be easily simplified using macros that are provided with it, which is all explained in this chapter. Methods on how to combat SPAM, one of the Internet's greatest nuisances, are also explained as are the steps needed to retrieve your mail from your sendmail server.

Chapter 22 - Monitoring Server Performance: Very detailed coverage on how to monitor your server 39;s performance, and even get Web-based Internet traffic graphs, using the SNMP, MRTG, Webalizer, TOP, VMSTAT and FREE utilities.

Chapter 23 - Advanced MRTG For Linux: Expanded coverage of MRTG, which explains how to get graphs of CPU, memory and disk usage statistics with examples.

Chapter 24 - The NTP Server: Explanations on how to synchronize the time on your Linux server with well-known time servers on the Internet, as well as how to make your Linux server the primary time source for your network.

Here is a more detailed list of topics to be found on the site taken from the table of contents listing of each chapter. Feel free to browse the listings to find what you need.

CHAPTER 1 - Why Host Your Own Site?: Tutorial topics include an Introduction; Our Network; Figure 1-1 : Wireless home network topology; Alternatives To In-House Web Hosting; Virtual Hosting; Dedicated Hosting; Factors To Consider Before Hosting Yourself; Table 1-1 The Pros and Cons of Web Hosting In-House; Is In-House Hosting Preferred?; How to Migrate from an External Provider; In-House Server Considerations; Conclusion.

CHAPTER 2 - Introduction to Networking: Tutorial topics include an Introduction; The OSI Networking Model; Table 2-1: The Seven OSI Layers; An Introduction to TCP/IP; TCP Is a Connection-Oriented Protocol; How TCP Establishes A Connection; UDP, TCP's "Connectionless" Cousin; TCP and UDP Ports; The TCP/IP "Time To Live" Feature; The ICMP Protocol and Its Relationship to TCP/IP; How IP Addresses Are Used To Access Network Devices; Private IP Addresses; The localhost IP Address; Network Address Translation (NAT) Makes Private IPs Public; Port Forwarding with NAT Facilitates Home-Based Web sites; DHCP; How DNS Links Your IP Address To Your Web Domain; IP Version 6 (IPv6); How Subnet Masks Group IP Addresses into Networks; Calculating The Number of Addresses Assigned to a Subnet; Table 2-2: The "Dotted Decimal" And "Slash" Subnet Mask Notations; Calculating the Range of Addresses on Your Network; Manual Calculation; Calculation Using a Script; Subnet Masks for the Typical Business DSL Line; The Physical and Link Layers; Networking Equipment Terminology; Network Interface Cards; The Meaning of the NIC Link Light; Duplex Explained; The MAC Address; How ARP Maps the MAC Address to Your IP Address; Common ARP Problems When Changing A NIC; The Two Broad Types Of Networking Equipment; Data Terminal Equipment; Data Communications Equipment; Using Straight-Through/Crossover Cables to Connect DTEs And DCEs; Table 2-3: Cabling Rules of Thumb; Connectivity Using Hubs; Using Switches as a Faster Alternative to Hubs; Local Area Networks; How Routers Interconnect LANs; How Simple Routing Works; Default Gateways, The Routers Of Last Resort; Firewalls Help Provide a Secure Routing Environment; Additional Introductory Topics; The File Transfer Protocol; Linux Help; Conclusion.

CHAPTER 3 - Linux Networking: Tutorial topics include an Introduction; How to Configure Your NIC's IP Address; Determining Your IP Address; Changing Your IP Address; Figure 3-1 - File formats for network-scripts; How DHCP Affects the DNS Server You Use; Multiple IP Addresses on a Single NIC; IP Address Assignment for a Direct DSL Connection; Some Important Files Created By adsl-setup; Simple Troubleshooting; IP Address Assignment for a Cable Modem Connection; How to Activate/Shut Down Your NIC; How to View Your Current Routing Table; How to Change Your Default Gateway; How to Configure Two Gateways; Adding Temporary Static Routes; Adding Permanent Static Routes; How to Delete a Route; Changing NIC Speed and Duplex; Using mii-tool; Setting Your NIC's Speed Parameters with mii-tool; Using ethtool; Setting Your NIC's Speed Parameters with ethtool; A Note About Duplex Settings; How to Convert Your Linux Server into a Simple Router; Configuring IP Forwarding; Configuring Proxy ARP; Configuring Your /etc/hosts File; The loopback Interface's localhost Entry; Debian / Ubuntu Network Configuration; The /etc/network/interfaces File; The auto Stanza; The mapping Stanza; The iface Stanza; Creating Interface Aliases; Adding Permanent Static Routes; A complete /etc/network/interfaces file; Conclusion.

CHAPTER 4 - Simple Network Troubleshooting: Tutorial topics include an Introduction; Sources of Network Slowness; Sources of a Lack of Connectivity; Doing Basic Cable and Link Tests; Testing Your NIC; Viewing Your Activated Interfaces; Viewing All Interfaces; Testing Link Status from the Command Line; Link Status Output from mii-tool; Link Status Output from ethtool; Viewing NIC Errors; Ifconfig Error Output; ethtool Error Output; netstat Error Output; Possible Causes of Ethernet Errors; How to See MAC Addresses; Using ping to Test Network Connectivity; Using telnet to Test Network Connectivity; Linux telnet Troubleshooting; Successful Connection; Connection Refused Messages; telnet Timeout or Hanging; telnet Troubleshooting Using Windows; Screen Goes Blank - Successful Connection; "Connect Failed" Messages; telnet Timeout or Hanging; Testing Web sites with the curl and wget Utilities; Using curl; Using wget; The netstat Command; The Linux iptables Firewall; Determining Whether iptables Is Running; How to Stop iptables; How to Configure iptables Rules; Using traceroute to Test Connectivity; Sample traceroute Output; Possible traceroute Messages; Table 4-1: traceroute Return Code Symbols; traceroute Time Exceeded False Alarms; traceroute Internet Slowness False Alarm; traceroute Dies At The Router Just Before The Server; Always Get a Bidirectional traceroute; ping and traceroute Troubleshooting Example; traceroute Web sites; Possible Reasons For Failed Traceroutes; Using MTR To Detect Network Congestion; Viewing Packet Flows with tcpdump; Table 4-2 : Possible TCPdump Switches; Table 4-3 : Useful tcpdump Expressions; Analyzing tcpdump files; Common Problems with tcpdump; Viewing Packet Flows with tshark; Table 4-4 : Possible tshark Switches; Table 4-5 : Useful tshark Expressions; Basic DNS Troubleshooting; Using nslookup to Test DNS; Using nslookup to Check Your Web site Name; Using nslookup To Check Your IP Address; Using nslookup to Query a Specific DNS Server; Using the host Command to Test DNS; Using nmap; Table 4-6 Commonly Used NMAP Options; Using netcat to Test Network Bandwidth; Determining the Source of an Attack; Who Has Used My System?; The last Command; The who Command; Conclusion.

CHAPTER 5 - Troubleshooting Linux With Syslog: Tutorial topics include an Introduction; syslog; Table 5-1 Syslog Facilities; The /etc/syslog.conf File; Activating Changes to the syslog Configuration File; How to View New Log Entries as They Happen; Logging syslog Messages to a Remote Linux Server; Configuring the Linux Syslog Server; Configuring the Linux Client; Syslog Configuration and Cisco Network Devices; Logrotate; The /etc/logrotate.conf File; Sample Contents of /etc/logrotate.conf; The /etc/logrotate.d Directory; Activating logrotate; Compressing Your Log Files; syslog-ng; The /etc/syslog-ng/syslog-ng.conf file; Figure 5-1 A Sample syslog-ng.conf File; Installing syslog-ng; Configuring syslog-ng Clients; Simple syslog Security; Conclusion.

CHAPTER 6 - Installing Linux Software: Tutorial topics include an Introduction; Where to Get Commonly Used Packages; Packages on Your Installation CDs; Manually Downloaded Packages; Table 6-1 Popular Package Download Sites; Automated Package Download; How to Download Software; Getting Software Using Web-Based FTP; Getting RPMs Using Command-Line Anonymous FTP; Table 6-2 FTP Commands; Getting Software Using wget; Installing Software From RPM Files; How To Install RPMs Manually; Using Downloaded Files; Using CD-ROMs; How to Install Source RPMs; RPM Installation Errors; Failed Dependencies; Signature Keys; How to List Installed RPMs; Listing Files Associated with RPMs; Listing Files for Already Installed RPMs; Listing Files in RPM Files; Listing the RPM to Which a File Belongs; Uninstalling RPMs; Which RPMs Will Start Up At Boot Time?; Automatic Updates with yum; Configuring yum; How to Automate yum; Creating Your Own yum Server; How to Automate yum; Keeping Your System current with Yum; Example of a yum Package Installation; Remember The Following Yum Facts; Installing Software From DEB Files; How To Install DEBs Manually; Using Downloaded Files; Using CD-ROMs; DEB Installation Errors; Failed Dependencies; How to List Installed DEBs; Table 6-3 Column Formatting for the dpkg command; Listing Files Associated with DEBs; Listing Files for Previously Installed DEBs; Listing Files in DEB Files; Listing the DEB Package to Which a File Belongs; Uninstalling DEBs; Which DEBs Will Start Up At Boot Time?; Automatic DEB Updates with apt-get; Configuring APT; Keeping Your System current with APT; Example of an apt-get Package Installation; Remember The Following APT Facts; Installing Software Using tar Files; Installing Perl Modules; Manual Installation of Perl Modules; Automatic Installation of Perl Modules; Conclusion.

CHAPTER 7 - The Linux Boot Process: Tutorial topics include an Introduction; The Linux Boot Sequence; Figure 7-1 Sample grub.conf file; Table 7-1 Linux Runlevels; Determining the Default Boot runlevel; Getting a GUI Console; Get a Basic Text Terminal Without Exiting the GUI; Using a GUI Terminal Window; Using Virtual Consoles; System Shutdown and Rebooting; Halt/Shut Down The System; Reboot The System; Entering Single-user Mode; Switching to Single-user Mode; Entering Single-user Mode At The Grub Splash Screen; Reverting To Your Default runlevel From Single User Mode; Root Password Recovery; Starting and Stopping Daemons; Starting a Daemon; Stopping a Daemon; Restarting a Daemon; The service command; Using chkconfig to Start Daemons at Each runlevel; chkconfig Examples; Use Chkconfig to Get a Listing of sendmail's Current Startup Options; Switch Off sendmail Starting Up in Levels 3 and 5; Double-check that sendmail Will Not Start Up; Turn On sendmail Again; Using chkconfig to Improve Security; Final Tips on chkconfig; Using sysv-rc-conf to Start Daemons at Each runlevel; Installing sysv-rc-conf; Listing the runlevels for Daemons; Setting the runlevels for Daemons; Conclusion.

CHAPTER 8 - Configuring A Linux DHCP Server: Tutorial topics include an Introduction; Download and Install the DHCP Package; The /etc/dhcpd.conf File; How to Get DHCP Started; DHCP Servers with Multiple NICs; Temporary Solution; Permanent Solution; Configuring Linux Clients to Use DHCP; Configuring Windows Clients to Use DHCP; Using a Single DHCP Server to Serve Multiple Networks; Simple DHCP Troubleshooting; DHCP Clients Obtaining 169.254.0.0 Addresses; Other DHCP Failures; Conclusion.

CHAPTER 9 - Adding Linux Users And Sudo: Tutorial topics include an Introduction; Who Is the Super User?; How To Add Users; How to Change Passwords; How to Delete Users; How to Tell the Groups to Which a User Belongs; How to Change the Ownership of a File; Using sudo; Simple Sudo Examples; Temporarily Gaining root Privileges; Becoming root for a Complete Login Session; Downloading and Installing the sudo Package; The /etc/sudoers File; Table 9-1 Format of the /etc/sudoers File; Simple /etc/sudoers Examples; Granting All Access to Specific Users; Granting Access To Specific Users To Specific Files; Granting Access to Specific Files as Another User; Granting Access Without Needing Passwords; Using Aliases in the sudoers File; Other Examples; Using syslog To Track All sudo Commands; Conclusion.

CHAPTER 10 - Configuring Samba: Tutorial topics include an Introduction; Download and Install Packages; How to Get Samba Started; The Samba Configuration File; Table 10-1 : File Format - smb.conf; How SWAT Makes Samba Simpler; Figure 10-1 Samba SWAT Main Menu; Basic SWAT Setup; Controlling SWAT; Encrypting SWAT; Create An stunnel User; Create The Certificates; Modify Certificate File Permissions; Create An /etc/stunnel/stunnel.conf Configuration File; Create A New /etc/xinetd.d File For Secure SWAT; Disable SWAT in the /etc/xinetd.d/swat File; Edit The /etc/services file To create a Secure SWAT entry; Activate swat-stunnel; Start stunnel; Test Secure SWAT; Test The Secure SWAT Login; Troubleshooting Secure SWAT; How To Make SWAT Changes Immediate; Creating A Starter Configuration; The [Global] Section; Table 10-2 : smb.conf Minimum Settings, "Global" Section; Using The SWAT Wizard; The [homes] Section; Table 10-3 : smb.conf Minimum Settings, "Home" Section; The [netlogon] and [profiles] Share Sections; The [printers] Share Section; Shares For Specific Groups Of Users; Samba Passwords; How To Create A Samba PDC Administrator User; Home Environment; Corporate Environment; How To Add Workstations To Your Samba Domain; Create Samba Trust Accounts For Each Workstation; Manual Creation Of Machine Trust Accounts (NT Only); Dynamic Creation of Machine Trust Accounts; Make Your PC Clients Aware Of Your Samba PDC; Windows 95/98/ME and Windows XP Home; Windows NT; Windows 200x and Windows XP Professional; How To Add Users To Your Samba Domain; Adding The Users In Linux; Create the user; Give them a Linux Password; Mapping The Linux Users To An smbpassword; Mapping A Private Windows Drive Share; Mapping Using "My Computer"; Mapping from the Command Line; Domain Groups And Samba; How To Delete Users From Your Samba Domain; How To Modify Samba Passwords; Table 10-4 : smb.conf Settings, Enabling Online Password Changes; Conclusion.

CHAPTER 11 - Sharing Resources with Samba: Tutorial topics include an Introduction; Adding A Printer To A Samba PDC; Adding The Printer To Linux; Figure 11-1 Printer Configuration Screen; Make Samba Aware of the Printer; Configure The Printer Driver On The Workstations; Creating Group Shares in SAMBA; Create The Directory And User Group; Configure The Share In SWAT; Map The Directory Using "My Computer"; Sharing Windows Drives Using a Linux SAMBA Client; Windows Setup; For Windows 98/ME; For Windows 2000; For Windows XP; Test Your Windows Client Configuration; Create A CD-ROM Drive Mount Point On Your Samba Server; Password Prompt Method; No Prompt Method; Using The smbmount Command Method; Automating Mounting With Linux SAMBA Clients; Conclusion.

CHAPTER 12 - Samba Security & Troubleshooting: Tutorial topics include an Introduction; Testing The smb.conf file; Samba and Firewall Software; Linux iptables; Windows-based Zone Alarm; The Windows XP Built In Firewall; Testing Basic Client / Server Network Connectivity; Testing Samba Client / Server Connectivity; Checking the Samba Logs; Samba Network Troubleshooting; Basic Samba Security; Conclusion.

CHAPTER 13- Linux Wireless Networking: Tutorial topics include an Introduction; Wireless Linux Compatible NICs; Common Wireless Networking Terms; Wireless Access Points; Service Set ID; Encryption; Wired Equivalent Privacy; Wi-Fi Protected Access; Networking With Linux Wireless-Tools; Using iwconfig For wireless-tools Configuration; Permanent wireless-tools Configuration; Fedora / RedHat; Debian / Ubuntu; WEP Encryption Configuration; WEP Encryption Configuration; #1.1 WEP Key Generation; Table 13-1 Byte Count to WEP Key Length Conversion; #1.2 WEP Key Configuration for Fedora / RedHat; #1.3 WEP Key Configuration for Debian / Ubuntu; WPA Encryption; Installing WPA Supplicant; The wpa_supplicant.conf File; Further WPA Configuration Steps - Fedora / RedHat; Further WPA Configuration Steps - Debian / Ubuntu; Configuring Linux with Incompatible Wireless NICs; Using bcm43xx-fwcutter with Broadcom Wireless Chips; How to tell if you have a Broadcom 43XX Chipset; Installing your Broadcom 43XX firmware; Configuring your Broadcom NIC; Using ndiswrapper; Installing and Configuring ndiswrapper; Networking With Linux-WLAN; Linux-WLAN Preparation; Identifying The Correct RPMs; Determine The Kernel Type; Determine The OS Version; Determine The Kernel Version; Installing the RPMs; Linux-WLAN Post Installation Steps; Configure The New wlan0 Interface; Disable Your Existing Ethernet NIC; Start Linux-WLAN; PCI Cards - Installed Using RPMs; PCMCIA Cards; Testing Linux-WLAN; Linux-WLAN WEP Encryption For Security; De-activating Encryption; Troubleshooting Your Wireless LAN; Check The NIC Status; The iwconfig Command; The iwlist Command; The iwspy Command; Check For Interrupt Conflicts; Kernel Errors; Can't Ping Default Gateway; "Unknown Device" Errors; Hermes Chipset Errors; ndiswrapper Errors; CONFIG_4KSTACKS errors During Installation; Incorrect Driver; NICs that are Incompatible with ndiswrapper; A Common Problem With Linux-WLAN And Fedora Core 1; Wireless Networks In Businesses; Conclusion.

CHAPTER 14 - Linux Firewalls Using iptables: Tutorial topics include an Introduction; What Is iptables?; Download And Install The Iptables Package; How To Start iptables; Determining The Status of iptables; Packet Processing In iptables; Table 14-1 Processing For Packets Routed By The Firewall; Figure 14-1 Iptables Packet Flow Diagram; Targets And Jumps; Table 14-2 Descriptions Of The Most Commonly Used Targets; Important Iptables Command Switch Operations; Table 14-2 General Iptables Match Criteria; Table 14-4 Common TCP and UDP Match Criteria; Table 14-5 Common ICMP (Ping) Match Criteria; Table 14-6 Common Extended Match Criteria; Using User Defined Chains; Table 14.7 Custom Queues Example Listing; Saving Your iptables Scripts; Fedora's iptables Rule Generator; Recovering From A Lost Script; Loading Kernel Modules Needed By iptables; Sample iptables Scripts; Basic Operating System Defense; Advanced iptables Initialization; Allowing DNS Access To Your Firewall; Allowing WWW And SSH Access To Your Firewall; Allowing Your Firewall To Access The Internet; Allow Your Home Network To Access The Firewall; Masquerading (Many to One NAT); Port Forwarding Type NAT (DHCP DSL); Static NAT; Troubleshooting iptables; Checking The Firewall Logs; iptables Won't Start; Conclusion.

CHAPTER 15 - Configuring a Linux FTP server: Tutorial topics include an Introduction; FTP Overview; Types of FTP; Figure 15-1 Active And Passive FTP Illustrated; Active FTP; Passive FTP; Regular FTP; Anonymous FTP; Problems With FTP And Firewalls; Client Protected By A Firewall Problem; Table 15-1 Client Protected by Firewall - Required Rules for FTP; Server Protected By A Firewall Problem; Table 15-2 outlines the general rules needed to allow FTP servers through a firewall.; How To Download And Install VSFTPD; How To Get VSFTPD Started; Testing the Status of VSFTPD; The vsftpd.conf File; Other vsftpd.conf Options; FTP Security Issues; The /etc/vsftpd.ftpusers File; Anonymous Upload; FTP Greeting Banner; Using SCP As Secure Alternative To FTP; Troubleshooting FTP; Tutorial; FTP Users with Only Read Access to a Shared Directory; Sample Login Session To Test Functionality; Conclusion.

CHAPTER 16 - Telnet, TFTP and XINETD: Tutorial topics include an Introduction; Managing xinetd Programs; Controlling xinetd; Controlling xinetd-Managed Applications; Telnet; Using The Telnet Client; Installing The Telnet Server Software; Setting Up A Telnet Server; Redhat / Fedora; Debian / Ubuntu; Basic Telnet Security; Let Telnet Listen On Another TCP Port; Let Telnet Allow Connections From Trusted Addresses; TFTP; Installing The TFTP Server Software; Configuring The TFTP Server; Redhat / Fedora; Debian / Ubuntu; Preparing TFTP Server Files; Saving Cisco Configurations To The TFTP Server; Cisco PIX firewall; Cisco Switch Running CATOS; Cisco Router; Cisco CSS 11000 "Arrowpoints"; Cisco Local Director; Uploading Cisco Configurations From The TFTP Server; Sample Upload Configuration File; Procedure To Upload A Configuration File; Using TFTP To Restore Your Router Configuration; Conclusion.

CHAPTER 17 - Secure Remote Logins & File Copying: Tutorial topics include an Introduction; A Quick Introduction To SSH Encryption; Starting OpenSSH; Testing The Status of SSH; The /etc/ssh/sshd_config File; SSH Versions 1 and 2; How To Change The TCP Port On Which SSH Listens; Using SSH To Login To A Remote Machine; What To Expect With Your First Login; SSH Failures Due To Linux Reinstallations; Deactivating Telnet After Installing SSH; Executing Remote Commands on Demand with SSH; SSH Tunneling; Local Forwarding; Remote Forwarding; Configuring Forwarding with GUI Clients; Troubleshooting SSH Port Forwarding; SCP: A Secure Alternative to FTP; Copying Files To The Local Linux Box; Copying Files To The Remote Linux Box; SFTP: Another Secure Alternative to FTP; Using SSH and SCP without a password; Configuration: Client Side; Configuration - Server Side; Conclusion.

CHAPTER 18 - Configuring DNS: Tutorial topics include an : Introduction; Introduction to DNS; DNS Domains; BIND; DNS Clients; Authoritative DNS Servers; How DNS Servers Find Out Your Site Information; When To Use A DNS Caching Name Server; When To Use A Static DNS Server; When To Use A Dynamic DNS Server; How To Get Your Own Domain; Basic DNS Testing of DNS Resolution; The Host Command; The nslookup Command; Downloading and Installing the BIND Packages; How To Get BIND Started; Redhat / Fedora; Debian / Ubuntu; The /etc/resolv.conf File; Table 18.1 Keywords In /etc/resolv.conf; Configuring A Caching Nameserver; Important File Locations; RedHat / Fedora; Table 18.2 Differences In Fedora And Redhat DNS File Locations; Debian / Ubuntu; Configuring A Regular Nameserver; Configuring resolv.conf; Preparing named.conf; Table 18.3 The Primary BIND Configuration Files; Configuring named.conf; Configuring The Zone Files; Time to Live Value; DNS Resource Records; The SOA Record; Table 18.4 The SOA Record Format; NS, MX, A And CNAME Records; Table 18.5 NS, MX, A, PTR and CNAME Record Formats; TXT Records; Sample Forward Zone File; Sample Reverse Zone File; BIND Views When Using NAT And DNS; The Internal View; The External View; The localhost_resolver View; Loading Your New Configuration Files; Make Sure Your /etc/hosts File Is Correctly Updated; Configure Your Firewall; Fix Your Domain Registration; Troubleshooting BIND; Configuration Troubleshooting Steps; Network Troubleshooting Steps; Migrating Your Web Site In-House; DHCP Considerations For DNS; Simple DNS Security; Zone Transfer Protection; Selectively Disabling Recursion; Naming Convention Security; Conclusion.

CHAPTER 19 - Dynamic DNS: Tutorial topics include an Introduction; Dynamic DNS Preparation; Testing ISP Connectivity For Your Website; Setup; Testing From The Internet; Test Port Forwarding; Registering DDNS; Install a DDNS Client On Your Server; Dynamic DNS And NAT Router/Firewalls; DDNS Client Software - SOHO Router / Firewalls; DDNS Client Software - Linux DDclient; The /etc/ddclient.conf file; How to Get DDclient Started; Finding DDclient Help; Testing Your Dynamic DNS; Conclusion.

CHAPTER 20 - Web Hosting With The Apache Web Server: Tutorial topics include an Introduction; Download and Install The Apache Package; How To Get Apache Started; Redhat / Fedora; Debian / Ubuntu; Configuring DNS For Apache; DHCP and Apache; General Configuration Steps; Where To Put Your Web Pages; The Default File Location; File Permissions And Apache; Security Contexts For Web Pages; Table 20-1 SELinux Security Context File Labels; Security Contexts For CGI Scripts; Named Virtual Hosting; Named Virtual Hosting Example; IP-Based Virtual Hosting; IP Virtual Hosting Example: Single Wild Card; IP Virtual Hosting Example: Wild Card and IP addresses; A Note On Virtual Hosting And SSL; Configuration - Multiple Sites And IP Addresses; Table 20-2 Web Hosting Scenario Summary; Testing Your Website Before DNS Is Fixed; Disabling Directory Listings; Handling Missing Pages; Using Data Compression On Web Pages; Compression Configuration Example; Apache Running On A Server Behind A NAT Firewall; Step 1: Configure Virtual Hosting on Multiple IPs; Step 2: Configure DNS "Views"; How To Protect Web Page Directories With Passwords; The conf.d Directory; Troubleshooting Apache; Testing Basic HTTP Connectivity; Browser 403 Forbidden Messages; Only The Default Apache Page Appears; Incompatible httpd.conf Files When Upgrading; Server Name Errors; The Apache Status Log Files; Table 20-3 Apache Log File Format; Table 20-4 HTTP Status Codes; The Apache Error Log Files; Conclusion.

CHAPTER 21 - Configuring Linux Mail: Tutorial topics include an Introduction; Configuring Sendmail; How Sendmail Works; Incoming Mail; Outgoing Mail; Sendmail Macros; Installing Sendmail; Starting Sendmail; How To Restart Sendmail After Editing Your Configuration Files; The /etc/mail/sendmail.mc File; How to Put Comments in sendmal.mc; Configuring DNS for sendmail; Configure Your Mail Server's Name In DNS; Configure The /etc/resolv.conf File; The /etc/hosts File; How To Configure Linux Sendmail Clients; Converting From a Mail Client to a Mail Server; A General Guide To Using The sendmail.mc File; The /etc/mail/relay-domains File; The /etc/mail/access File; The /etc/mail/local-host-names File; Which User Should Really Receive The Mail?; The /etc/mail/virtusertable file; The /etc/aliases File; Sendmail Masquerading Explained; Configuring masquerading; Testing Masquerading; Other Masquerading Notes; Using Sendmail to Change the Sender's Email Address; Troubleshooting Sendmail; Testing TCP connectivity; Further Testing of TCP connectivity; The /var/log/maillog File; Common Errors Due To Incomplete RPM Installation; Incorrectly Configured /etc/hosts Files; Fighting SPAM; Using Public SPAM Blacklists With Sendmail; Spamassassin; Downloading And Installing Spamassassin; Starting Spamassassin; Configuring procmail for spamassassin; Configuring Spamassassin; Testing spamassassin; Startup spamassassin; Tuning spamassassin; The Rules du Jour Spamassassin Tool; The /etc/rulesdujour/config Configuration File; Installing Rules du Jour; Using Greylisting; Downloading and Installing milter-greylist; Configuring milter-greylist; Configuring milter-greylist; A Simple PERL Script To Help Stop SPAM; Configuring Your POP Mail Server; Installing Your POP Mail Server; Starting Your POP Mail Server; The /etc/dovecot.conf File; How To Configure Your Windows Mail Programs; Configuring Secure POP Mail; How to handle overlapping email addresses.; Troubleshooting POP Mail; Conclusion.

CHAPTER 22 - Monitoring Server Performance: Tutorial topics include an : (See Chapter 23 for advanced MRTG Topics); Introduction; SNMP; OIDs And MIBs; Figure 22-1 SNMP OID Structure; Table 22-1 OIDs And Their Equivalent MIBs; SNMP Community Strings; SNMP Versions; Doing SNMP Queries; Installing SNMP Utilities on a Linux Server; SNMP Utilities Command Syntax; Configuring Simple SNMP on a Linux Server; SNMP On Other Devices; Basic SNMP Security; SNMP Versions 1 and 2; SNMP Version 3; Simple SNMP Troubleshooting; MRTG; Figure 22-2 A Typical MRTG Web Page; MRTG Download and Installation; Configuring MRTG; Getting MRTG To Poll Multiple Devices; Configuring Apache To Work With MRTG; Basic Security; How To View The MRTG Graphs In Your Web Browser; Using MRTG To Monitor Other Subsystems; Troubleshooting MRTG; Basic Steps; Setting The Correct Character Set; Fedora Core 1 MRTG Errors With Net-SNMP; Webalizer; How To View Your Webalizer Statistics; The Webalizer Configuration File; The top Command; The vmstat Command; The free Utility; Conclusion.

CHAPTER 23 - Advanced MRTG (CPU, Memory, Disk and TCP Connections: Tutorial topics include an : Monitoring); Introduction; Locating And Viewing The Contents Of Linux MIBs; Testing Your MIB Value; Differences In MIB And MRTG Terminology; The CPU And Memory Monitoring MIB; Table 23-1 Important Objects In The UCD-SNMP-MIB MIB; The TCP/IP Monitoring MIB; Table 23-2 Important Objects In The TCP-MIB MIB; Manually Configuring Your MRTG File; Parameter Formats; Legend Parameters; Options Parameters; Scaling Parameters; Defining The MIB Target Parameters; Table 23-3 Mapping MIBs To The Graph Legends; Plotting Only One MIB Value; Adding MIB Values Together For a Graph; Sample Target: Total CPU Usage; Sample Target: Memory Usage; Sample Target: Newly Created Connections; Sample Target: Total TCP Established Connections; Sample Target: Disk Partition Usage; Defining Global Variables; Implementing Advanced Server Monitoring; A Complete Sample Configuration; Testing The Configuration; Creating A New MRTG Index Page To Include This File; Configuring cron To Use The New MRTG File; Monitoring Non Linux MIB Values; Scenario; Testing The OIDs; Speeding up MRTG with RRDtool; Scenario; Installing RRDtool; Storing the MRTG Data in RRDtool Format; The MRTG / RRDtool Integration Script; Troubleshooting; Conclusion.

CHAPTER 24 - Configuring NTP: Tutorial topics include an : Introduction; Download and Install The NTP Package; The /etc/ntp.conf File; How To Get NTP Started; Verifying NTP is Running; Doing An Initial Synchronization; Determining If NTP Is Synchronized Properly; Your Linux NTP clients cannot Synchronize Properly; Fedora Core 2 File Permissions; Configuring Cisco Devices To Use An NTP Server; Cisco IOS; CATOS; NTP Security; Firewalls and NTP; NTP Authentication; Configuring A Windows NTP Client; Conclusion.

CHAPTER 25 - Network Based Linux Installation: Tutorial topics include an Introduction; Setting Up The Installation Server; Basic Preparation; Create The Installation Directories; Copying The Files; HTTP & FTP Preparation; NFS Preparation; Setup Your Webserver; Setup Your FTP Server; Create A Special FTP User; Setup Your NFS Server; Configure Your DHCP Server; Creating A Boot CD; The Network Installation; If You Selected The NFS Method; If You Selected The HTTP Method; If You Selected The FTP Method; Troubleshooting The Network Installation; Automating Installation With Kickstart; How To Create New Kickstart Configuration Files; Adding Post Installation Commands; A Note About Using anaconda-ks.cfg; How To Run A Kickstart Installation; Using a NFS Server; Using a Web Server; Booting With Your Kickstart Files; Conclusion.

CHAPTER 26 - Linux Software RAID: Tutorial topics include an Introduction; RAID Types; Linear Mode RAID; RAID 0; RAID 1; Figure 26-1 RAID 0 And RAID 1 Operation; RAID 4; RAID 5; Figure 26-2 RAID 5 Operation; Before You Start; IDE Drives; Serial ATA Drives; SCSI Drives; Should I Use Software RAID Partitions Or Entire Disks?; Backup Your System First; Configure RAID In Single User Mode; Configuring Software RAID; RAID Partitioning; Determining Available Partitions; Unmount the Partitions; Prepare The Partitions With FDISK; Use FDISK Help; Set The ID Type To FD; Make Sure The Change Occurred; Save The Changes; Repeat For The Other Partitions; Preparing the RAID Set; Create the RAID Set; Confirm RAID Is Correctly Inititalized; Format The New RAID Set; Create the mdadm.conf Configuration File; Create A Mount Point For The RAID Set; Edit The /etc/fstab File; Mount The New RAID Set; Check The Status Of The New RAID; Conclusion.

CHAPTER 27 - Expanding Linux Partitions With LVM: Tutorial topics include an Introduction; Adding Disks To Linux; Scenario; Determining The Disk Types; Preparing Partitions on New Disks; Verifying Your New Partition; Putting A Directory Structure On Your New Partition; Migrating Data Over To your New Partition; Expanding Partitions With LVM; Configuring LVM Devices; Backup Your Data; Unmount your /home filesystem; Determine The Partition Types; Start FDISK; Set The ID Type T o 8e; Make Sure The Change Occurred; Save The Partition Changes; Define Each Physical Volume; Run VGscan; Create A Volume Group For the PVs; Create A Logical Volume From The Volume Group; Format The Logical Volume; Create A Mount Point; Update The /etc/fstab File; Mount The Volume; Restore Your Data; Get Out Of Single User Mode; Conclusion.

CHAPTER 28 - Managing Disk Usage With Quotas: Tutorial topics include an Introduction; Setting Up Quotas; Enter Single-User Mode; Edit Your /etc/fstab File; Remount The Filesystem; Get Out of Single-user Mode; Create The Partition Quota Configuration Files; Initialize The Quota Table; Edit The User's Quota Information; Testing; Other Quota Topics; Editing Grace Periods; Editing Group Quotas; Getting Quota Reports; Conclusion.

CHAPTER 29 - Remote Disk Access With NFS: Tutorial topics include an Introduction; NFS Operation Overview; General NFS Rules; Key NFS Concepts; VFS; Stateless Operation; Caching; NFS And Symbolic Links; NFS Background Mounting; Hard and Soft Mounts; NFS Versions; Important NFS Daemons; Installing NFS; Scenario; Configuring NFS on The Server; The /etc/exports File; Starting NFS on the Server; Configuring NFS on The Client; Starting NFS on the Client; NFS And DNS; Making NFS Mounting Permanent; The /etc/fstab File; Table 29.1 Possible NFS Mount Options; Permanently Mounting The NFS Directory; Manually Mounting NFS File Systems; Activating Modifications To The /etc/exports File; New Exports File; Adding A Shared Directory To An Existing Exports File; Deleting, Moving Or Modifying A Share; The NFS Automounter; Automounter Map Files; Direct Maps; Indirect Maps; The Structure Of Direct And Indirect Map Files; Indirect Map File Example; Direct Map File Example; Wildcards In Map Files; Using the Ampersand Wildcard; Using the Asterisk Wildcard; Starting Automounter; Automounter Examples; Troubleshooting NFS; Table 29.2 Some Common NFS Error Messages; The showmount Command; The "df" Command; The nfsstat Command; Table 29.3 Error Thresholds For The "nfsstat" Command; Other NFS Considerations; Security; NFS Hanging; File Locking; Nesting Exports; Limiting root Access; Restricting Access to the NFS server; File Permissions; Conclusion.

CHAPTER 30 - Centralized Linux Logins With NIS: Tutorial topics include an Introduction; Scenario; Configuring The NFS Server; Configuring The NFS Client; Configuring The NIS Server; Install the NIS Server Packages; Edit Your /etc/sysconfig/network File; Edit Your /etc/yp.conf File; Start The Key NIS Server Related Daemons; Table 30-1 Required NIS Server Daemons; Initialize Your NIS Domain; Start The ypbind and ypxfrd Daemons; Make Sure The Daemons Are Running; Adding New NIS Users; Configuring The NIS Client; Run authconfig; Start The NIS Client Related Daemons; Verify Name Resolution; Test NIS Access To The NIS Server; Test Logins via The NIS Server; Logging In Via Telnet; Logging In Via SSH; NIS Slave Servers; Configuring NIS Slave Servers; Table 30-2 NIS Master / Slave /etc/hosts Files; Table 30-3 NIS Master / Slave /etc/yp.conf Files; Configuring NIS Clients With Slaves; Changing Your NIS Passwords; When There Is Only An NIS Master; Users Changing Their Own Passwords; User "Root" Changing Passwords; When There Is A NIS Master / Slave Pair; Possible Password Errors; Segmentation Faults; Daemon Errors; Considerations For A Non NFS Environment; NIS Troubleshooting; Conclusion.

CHAPTER 31 - Centralized Linux Logins With LDAP And RADIUS: Tutorial topics include an Introduction; The LDAP Directory Structure; Scenario; Downloading And Installing The LDAP Packages; Required LDAP Server RPMS; Required LDAP Client RPMS; Configuring The LDAP Server; Create a database directory; Create an LDAP "root" password; Edit the slapd.conf file; Start the LDAP daemon; Convert the /etc/passwd file to LDIF format; Create the ldapuser test account; Extract the desired records from /etc/passwd; Find the conversion script; Convert the ".ldapuser" file; Modify the LDIF files; Edit the user LDIF file; Create an LDIF file for the "example.com" domain; Import the LDIF files into the database; Test the LDAP database; Configuring The LDAP Client; Edit the ldap.conf configuration file; Edit the /etc/nsswitch file; Create Home Directories On The LDAP Client; Check if ldapuser is Missing From the /etc/passwd file; Create The Home Directory For ldapuser On The LDAP Client; Testing; Configuring Encrypted LDAP Communication; Using Transport Layer Security (TLS)Encryption; How TLS Communication Works; Configuring the TLS Server; Configuring the TLS Client; TLS Maintenance; Using stunnel Encryption; Configuring the stunnel LDAP client; Configuring the stunnel LDAP server; Troubleshooting LDAP Logins; Check Your /var/log/messages file; Testing Basic Connectivity; Testing Using ldapsearch; Use SSH or the Linux console; Use the tcpdump Command; Testing Regular LDAP; Testing Secure LDAP; LDAP Works but not When I Switch to LDAPS; Stunnel Doesn't Appear To Work; LDAP_BIND Errors; Possible stunnel Errors in Fedora Core 2; Common LDAP Administrative Tasks; Starting and Stopping LDAP; LDAP users changing their own passwords; Modifying LDAP users by user "root"; The Modify LDAP User Script; Adding new LDAP users; Create an LDAP Add User Script; Add the User to the Database; Deleting LDAP users; LDAP Web Management Tools; Configuring RADIUS for LDAP; How To Download and Install The FreeRADIUS Packages; Starting and Stopping FreeRADIUS; Configuring The /etc/raddb/radiusd.conf File; Configuring The /etc/raddb/users File; Configuring The /etc/raddb/clients.conf File; Troubleshooting And Testing RADIUS; Server Setup; Linux Client Setup; Cisco Client Setup; Errors With Fedora Core 2; Conclusion.

CHAPTER 32 - Controlling Web Usage With Squid: Tutorial topics include an Introduction; Download and Install The Squid Package; Starting Squid; The /etc/squid/squid.conf File; The Visible Host Name; Access Control Lists; Restricting Web Access By Time; Restricting Access to specific Web sites; Restricting Web Access By IP Address; Password Authentication Using NCSA; Forcing Users To Use Your Squid Server; Making Your Squid Server Transparent To Users; Squid Transparent Proxy Configuration; Configuring iptables to Support the Squid Transparent Proxy; Manually Configuring Web Browsers To Use Your Squid Server; Squid Disk Usage; Troubleshooting Squid; Conclusion.

CHAPTER 33 - Modifying The Kernel To Improve Performance: Tutorial topics include an Introduction; Table 33-1: Kernels Found On Fedora Installation CDs; The Pros And Cons Of Kernel Upgrades; The Kernel Sources Package; Installing Kernel Sources; Kernel Modules; Reasons For Kernel Modules; How Kernel Modules Load When Booting; Modules And The grub.conf File; Loading Kernel Modules On Demand; Creating A Custom Kernel; Make Sure Your Source Files Are In Order; The ".config" File; Backup Your Configuration; Customizing The ".config" File; Table 33-2 Scripts For Modifying The .config File; Table 33-3 Kernel Option Choices; Table 33-4 Kernel Configuration Options; Configure Dependencies; Edit The Makefile To Give The Kernel A Unique Name; Compile A New Kernel; Build The Kernel's Modules; Copy The New Kernel To The /boot Partition; Updating GRUB; Kernel Crash Recovery; How To Create A Boot CD; Updating The Kernel Using RPMs; Conclusion.

CHAPTER 34 - Basic MySQL Configuration: Tutorial topics include an Introduction; Preparing MySQL For Applications; Installing MySQL; Starting MySQL; The /etc/my.cnf File; The Location of MySQL Databases; Creating a MySQL "root" Account; Accessing The MySQL Command Line; Granting Privileges to Users; Running MySQL Scripts To Create Data Tables; Viewing Your New MySQL Databases; Listing The Data Tables In Your MySQL Database; Viewing Your MySQL Database's Table Structure; Viewing The Contents Of A Table; Configuring Your Application; Table 34.1 Required PHP and Perl RPMs for MySQL Support; Recovering / Changing Your MySQL Root Password; MySQL Database Backup; MySQL Database Restoration; MySQL Table Backup and Restoration; Very Basic MySQL Network Security; Basic MyQL Troubleshooting; Connectivity Testing; Test Database Access; A Common Fedora Core 1 MySQL Startup Error; Conclusion.

Chapter 35 - Linux VPN Configuration: Tutorial topics include an Introduction; VPN Guidelines; Scenario; Figure 35-1 Openswan Topolology Diagram; Download And Install The Openswan Package; How to get Openswan Started; How to fix common Status errors; IP forwarding; Opportunistic Encryption DNS Checks:; VPN Configuration Steps (Using RSA Keys); The /etc/ipsec.conf file; Table 35-1 Parameters of the /etc/ipsec.conf file; Obtaining RSA Keys; Creating Your Own Keys; Get The Left Public Key; Get The Right Public Key; Some Important Notes About The /etc/ipsec.conf File; Restart Openswan; Initialize The New Tunnel; Testing The New Tunnel; Possible Changes To IP Tables NAT/Masquerade Rules; How To Ensure Openswan Starts When Rebooting; Using Pre-Shared Keys (PSK); Troubleshooting Openswan; Determine the Tunnel Status; Testing VPN Connectivity; Check The Routes; Using TCPdump; Protected Interface TCPDUMP Output From "vpn2"; Unprotected Interface TCPDUMP Output From "vpn2"; Check Syslog Error Messages; "Invalid Key" Messages; Conclusion.

APPENDIX I - Miscellaneous Topics: Tutorial topics include an Introduction; Fedora Core 3; Linux Security With TCP Wrappers; The TCP Wrappers File Format; Determining the TCP Daemon's Name; Additional TCP Wrappers Help; Adjusting Kernel Parameters; Running Linux Without A Monitor; Preparing To Go "Headless"; Configuration Steps; Table I.1 How Physical COM Ports Map To Linux TTYS Devices; Make Your Linux Box Emulate A VT100 Dumb Terminal; Configuration Steps; VPN Terms and Methods; Figure I.1 Transport mode AH packet format; Figure I.2 Transport mode AH / ESP packet format; Figure I.3 Tunnel mode AH packet format; Figure I.4 Tunnel mode AH / ESP packet format; Authentication and Encryption methods; Internet Key Exchange (IKE); Public Encrypted Keys; Private Shared keys; IKE's role in creating Security Associations; VPN Security And Firewalls; VPN User Authentication Methods For Temporary Connections; Table I-2 Types Of Dial Up VPN Authentication; TCP/IP Packet Format; Figure I.5; Table I.3 Contents Of The IP Header; Table I.4 Contents Of The TCP Header; Table I.5 Contents Of The UDP Header; ICMP Codes; Table I-6 ICMP Codes. Conclusion.

APPENDIX II - Codes, Scripts & Configurations: Tutorial topics include an : Subnet Calculator Script; Apache File Permissions Script; Sendmail SPAM Filter Script; IPtables Basic Initialization Script; IPtables Firewall As A Webserver Script; IPtables IP Masquerading Script; IPtables Port Forwarding Script; IPtables Complex script; DNS Zone File For my-site.com; DNS Zone File For my-other-site.com; Forward Zone File For A Home Network Using NAT; Reverse Zone File For A Home Network Using NAT; Sendmail Sample /etc/mail/access File; Sendmail Sample /etc/aliases File; Sendmail Sample /etc/mail/local-host-names File; Sendmail Sample /etc/mail/sendmail.mc File; Sendmail Sample /etc/mail/virtusertable File; Conclusion

APPENDIX III - Configuring Syslog On Cisco Devices: Tutorial topics include an Introduction; Cisco Routers; Catalyst CAT Switches running CATOS; Cisco Local Director; Table IV-1 Syslog Facility and Severity Numbering Scheme for Local Directors; Cisco PIX Filewalls; Table IV-2 Syslog Facility and Severity Numbering Scheme for PIX Firewalls; Cisco CSS11000 (Arrowpoints); The Sample Cisco syslog.conf File: Tutorial topics include an ;