Using and Administering Linux: Volume 3 : Zero to SysAdmin: Network Services

Manage complex systems with ease and equip yourself for a new career. This book builds upon the skills you learned in Volumes 1 and 2 of this course and it depends upon the virtual network and virtual machine you created there. However, more experienced Linux users can begin with this volume and download an assigned script that will set up the VM for the start of Volume 3. Instructions with the script will provide specifications for configuration of the virtual network and the virtual machine. Refer to the volume overviews in the book's introduction to select the volume of this course most appropriate for your current skill level. Start by reviewing the administration of Linux servers and install and configure various Linux server services such as DHCP, DNS, NTP, and SSH server that will be used to provide advanced network services. You'll then learn to install and configure servers such as BIND for name services, DHCP for network host configuration, and SSH for secure logins to remote hosts. Other topics covered include public/private keypairs to further enhance security, SendMail and IMAP and antispam protection for email, using Apache and WordPress to create and manage web sites, NFS, SAMBA, and Chrony. This volume also covers SELinux, and building RPMs to distribute automation scripts. All of these services are installed on a single server host over the course of the book and by the time you are finished you will have a single server that provides these services for your network. **What You Will Learn** Install, configure, and manage several Linux server services such as email with spam management and single and multiple web sites Work with NTP time synchronization, DHCP, SSH, and file sharing with Unix/Linux and Windows clients Create RPMs for distribution of scripts and administrative programs. Understand and work with enhanced security. **Who This Book Is For** Those who are already Linux power users - SysAdmins who can administer Linux workstation hosts that are not servers - who want to learn to administer the services provided by Linux servers such as web, time, name, email, SSH, and more. Table of Contents......Page 5 About the Author......Page 16 About the Technical Reviewer......Page 17 Acknowledgments......Page 18 Introduction......Page 19 Overview......Page 30 Creating the VM......Page 31 Installing Linux......Page 32 Exercises......Page 34 Network configuration......Page 35 Exercises......Page 47 Overview of DHCP......Page 48 Installing the DHCP server......Page 49 Configuring the DHCP server......Page 51 Configuring guest hosts......Page 56 The dhcpd.conf file......Page 58 Exercises......Page 59 Introducing Domain Name Services......Page 60 The /etc/hosts file......Page 61 How a name search works......Page 63 The DNS database......Page 65 SOA......Page 69 NS......Page 70 CNAME......Page 71 MX......Page 72 Preparation......Page 73 Setting up the caching name server......Page 74 Configuring IPTables for DNS......Page 77 Start the name service......Page 80 Reconfiguring DHCP......Page 82 Using the top-level DNS servers......Page 83 Creating the forward zone file......Page 84 Adding the forward zone files to named.conf......Page 85 Adding CNAME records......Page 87 Creating the reverse zone file......Page 89 Add the reverse zone to named.conf......Page 90 Exercises......Page 93 Introduction......Page 94 Starting the SSH server......Page 95 How SSH works – briefly......Page 97 Public/Private Key Pairs......Page 98 How PPKPs work......Page 99 X-forwarding......Page 105 The X Window System......Page 107 Remote commands......Page 108 Remote backups......Page 110 Chapter summary......Page 111 Exercises......Page 112 Introduction......Page 114 NIC configuration files......Page 116 Create an interface configuration File......Page 117 The interface configuration file......Page 120 Routing on a workstation......Page 123 Network routing......Page 124 Creating a router......Page 126 Preparation......Page 127 Configure the new NIC......Page 128 Reconfiguring DHCP......Page 129 Reconfiguring DNS......Page 133 Kernel configuration......Page 137 Changing the firewall......Page 139 Understanding the rule set......Page 140 Complex routing......Page 145 Fail2Ban......Page 146 Exercises......Page 150 Introduction......Page 151 Definitions......Page 152 Email data flow......Page 153 Email headers......Page 155 Sendmail installation......Page 160 SendMail configuration......Page 161 Firewall and DNS configuration......Page 171 SendMail on the client......Page 173 SMTP – The protocol......Page 176 Email-only accounts......Page 180 Who gets email for root?......Page 181 There is no delivery guarantee......Page 183 Exercises......Page 184 Introduction......Page 185 More mailx......Page 186 Configuring IMAP on the server......Page 189 Thunderbird......Page 192 Adding authentication......Page 196 IMAP authentication......Page 197 More about ports......Page 201 Chapter summary......Page 211 Exercises......Page 212 Introduction......Page 213 The problem......Page 214 My email server......Page 215 Project requirements......Page 216 Procmail......Page 217 How it works......Page 218 Preparation......Page 219 Configuring SendMail......Page 220 Hacking mimedefang-filter......Page 221 Setting up a mail folder......Page 228 Configuring Procmail......Page 229 Creating SpamAssassin rules......Page 232 Chapter summary......Page 238 Exercises......Page 239 Introduction......Page 240 Testing Apache......Page 241 Creating a simple index file......Page 244 Adding DNS......Page 246 Using Telnet to test the web site......Page 247 Good practice configuration......Page 248 Configuring the primary virtual host......Page 249 Configuring the second virtual host......Page 251 Using Perl......Page 253 Using BASH......Page 255 Redirecting the web page to CGI......Page 256 Chapter summary......Page 258 Exercises......Page 259 Introduction......Page 260 Install PHP and MariaDB......Page 261 Install WordPress......Page 262 HTTPD configuration......Page 264 Creating the WordPress Database......Page 265 Configuring WordPress......Page 266 Administering WordPress......Page 269 Updating WordPress......Page 271 Exploring MariaDB......Page 272 Chapter summary......Page 274 Exercises......Page 275 Introduction......Page 276 Integrating MailMan with Apache......Page 277 Site mailing list......Page 278 Create a mailing list......Page 281 Configuring the new list......Page 282 Changing list defaults......Page 284 The user interface......Page 285 Rejections from large email services......Page 287 Documentation......Page 288 Exercises......Page 289 Introduction......Page 290 File sharing use cases......Page 291 Preparation......Page 293 Installation and preparation of VSFTP......Page 296 The FTP client......Page 299 Firewall configuration for FTP......Page 301 Active mode......Page 302 Passive mode......Page 303 Setting the firewall rules......Page 304 Anonymous FTP access......Page 305 Securing VSFTP with encryption......Page 307 NFS server......Page 309 NFS client......Page 316 Cleanup......Page 317 SAMBA......Page 318 Using the SAMBA client......Page 324 Midnight Commander......Page 327 Apache web server......Page 331 Chapter summary......Page 337 Exercises......Page 338 Introduction......Page 340 TigerVNC......Page 341 Security......Page 346 Blank TigerVNC view screen......Page 348 Exercises......Page 349 Linux and time......Page 351 The NTP server hierarchy......Page 352 NTP choices......Page 353 Client configuration......Page 354 Configuring the NTP server......Page 358 Configuring the client and testing......Page 360 chronyc as an interactive tool......Page 362 Setting the hardware clock......Page 363 About time zones......Page 364 Chapter summary......Page 367 Exercises......Page 368 Introduction......Page 369 Enabling bind-chroot......Page 370 Hardening the network......Page 374 Advanced iptables......Page 376 Advanced backups......Page 379 rsync......Page 380 Performing backups......Page 384 Restrict SSH remote root login......Page 387 Root kits......Page 388 Clam-AV......Page 393 Tripwire......Page 395 SELinux......Page 398 Social engineering......Page 404 Exercises......Page 405 Introduction......Page 407 Preparation......Page 408 Preamble......Page 412 %prep......Page 414 %files......Page 415 %postun......Page 416 %changelog......Page 417 Building the RPM......Page 418 Testing the RPM......Page 420 Experimenting......Page 421 Chapter summary......Page 422 Exercises......Page 423 Curiosity......Page 424 Convert......Page 425 Tools......Page 426 Resources......Page 427 Compiling the kernel......Page 428 Chapter summary......Page 429 Books......Page 431 Web sites......Page 432 Index......Page 437