The micro-course contains a description of the FreeRadius system, its installation and configuration. It is the most popular free RADIUS server in the Linux system used in many implementations of IT systems for computer networks.
Keywords: freeradius, huntgroups, radiusd.conf, clients.conf, radiusd
Micro-course generally discusses the dynamic routing protocols, their advantages and disadvantages. Autonomous System concept is introduced. The reader finds out what lies at the root of the Internet, what determines which path the traffic is transmitted through. We try to explain "why sometimes packages from London to Manchester go through Frankfurt."
The Micro-course describes the way of detecting hardware from the level of the Linux operating system. It discusses the main files where this information is saved on the system start as well as commands enabling collection of such information. An example of such a command is the discussed in the micro-course hwinfo command.
Fibre optics have already entered into the thatch. There is a number of ISPs that offer access to their resources through the installation of fiber optic connections at home. Fiber optic technology is present in LAN, MAN and WAN. We discuss in this course such issues as: The principle of operation of the optical fiber systems, Multi-mode and single mode systems Construction of fiber-optic connection systems (POP) and fiber panels. We present the most popular fiber connectors. Ethernet 100 Mbps, 1,10,40 and 100 Gbps technologies are discussed, which use optical paths for data transmission. Elements of the design and installation of fiber optic networks are also provided. This course is required for installers of structured cabling systems, and is part of a series of design practical micro-courses.
Introduction to the operation of the IMAP protocol, the one which enables remote management of inbox. We discuss how the e-mail directories are managed, how to synchronize e-mails on the local computer and the remote inbox. A sample client and IMAP server session communication is shown.
The micro-course describes the procedure of installing and configuring the GrSecurity mechanism. It introduces a lot of protection in the Linux system kernel. The example protection is the possibility to create access lists based on Role-Based Access Control (RBAC), the possibility to impose additional restrictions on the chroot environment, the possibility to switch on the event registration mode or using random numbers for IP source ports and the PID process identifiers.
Keywords: grsecurity, paxctl, pspax. scanelf, dumpelf, execstack, paxtest, paxtest, gradm, RBAC, pollicy
Micro-course describes the family of DSL transmission technology which is mainly used to connect customers to the Internet using a modem. The course presents DSL starting from the description of the operation, the introduction of the basic concepts, to the demonstration of the advantages and disadvantages of the major protocols of this family: - ADSL (Asymmetric DSL full rate), - RADSL (Rate Adaptive DSL), - SDSL (Symmetric DSL), HDSL (High data rate DSL), - VDSL (Very high bit rate DSL), - IDSL (Integrated Services Digital Network DSL). The second part presents the Frame Relay technology, which is used to connect WAN network to local area network (LAN) or to connect LAN to the Internet. The course begins with explanation of the principles and introduces the basic concepts that are specific for Frame Relay. The mechanisms operating in the network are presented in relation to the structure of the FR frame. The course deals also with types of signaling in the FR networks and mechanism to communicate the status of a virtual circuit as well as FR transmission parameters such as guaranteed bandwidth.
The importance of the DNS server is known to every person using its resources such as electronic mail or WWW. The micro-course discusses the way of installing and configuring the ISC BIND server, the way of creating zones and entries in the base for particular domain records.
Keywords: BIND, named, named.conf, zone
The micro-course presents configuration and administration of a few popular servers of POP - POPA3D, Solid-POP3D and Cyrus POP3D. Moreover, it describes a few popular mechanisms of supporting mailboxes such as mpop, fetchmail or fakepop.
Keywords: pop3d, solid-pop3d, cyrus pop3d, mpop, fetchmail, mpop, fakepop, POP, POP3
The introduction of general concepts for understanding the structure of Linux. There are some definitions which the administrator uses to describe the system and the problems encountered. In almost non-technical way, the basic concepts are explained, such as the kernel or command interpreter.
The process of installing and configuring the Debian distribution is presented here, step by step. Starting from partitioning, configuring the time zone up to setting up passwords. As a result, you will get ready to use operating system.
We live our lives in Internet era - it's a fact. Shopping, payments and money management are all subjects of online transactions too. Consequently it is necessary to ensure the safety of online transactions. That's what SSL protocol does. SSL is the main topic discussed in this micro course. Additionally, the course shows an example of configuring Stunnel package, which is used to secure any communictaion service with an encrypted SSL channel.
A description of the network layer monitoring on the basis of the Netflow system. The micro-course describes how to create procedures of collecting network statistics, what the Netflow protocol is, what its versions are and where they are used. Moreover, simple tools used for monitoring network interfaces were described.
Keywords: iptraf, stark, etherape bmon, iptotal, netflow, ipfix, frame, netflow v5, próbnik NetFlow, OAM, OAM&P
DHCP is currently the most widely protocol used for dynamic assigning the workstation settings like the IP address, subnet mask, gateway, DNS server addresses, domain name, etc. In this micro-course we discuss the basics of DHCP. We show how to run a DHCP server and also we mention the safety aspects of the services.
Description of SMTP, the main protocol by which email messages are sent between the client and the server and between servers. Session of communication between two devices is shown. How to verify the server? All these issues can be found in the micro-course.
This micro-course describes basic elements used by the system kernel in order to organize the system work. In this material you can find information about what the process is, how it communicates with processes, and how communication between two processes works.
The micro-course discusses configuration of the Apache server, httpd.conf and htaccess configuration files. It describes the most important commands of the configuration file and their meaning and examples. If you want to implement the WWW server in your own company, this micro-course is necessary to do this task quickly.
Keywords: httpd.conf, htaccess, DirectoryRoot
Most administrators are used to a raw text mode where the menu is displayed by writing a line with an option choice under the cursor. Introducing the ncurses library in the Linux system enables creation of smart and full-screen applications in the text mode which work is much nicer with. The basic program supporting controls and graphic elements in the text mode is the dialog command which was described in detail in this micro-course.
Micro-course concentrates on operation of FTP - the protocol used to transfer files over the Internet. - It is the oldest protocol, which main task is two-way file transfer. Nowadays more and more popular are HTTP protocols - small files are downloaded directly from a web page or the BitTorrent protocol is used for the propagation of large files. However, for example, when creating a file repository for third party company (eg leaflets, high-resolution product images) the FTP is still unreplaceable. The course describes how to test the FTP server on the basis of information about the operation of this protocol. The course also explains why some older firewalls cannot handle this protocol and how to fix it.
This micro-course describes configuration of the mail system based on the Sendmail server. It is one of the oldest implementations of the SMTP server in Linux/Unix systems. This system became a prototype for other solutions of this type.
Keywords: semdmail, mail, SMTP
The Linux distribution, as well as the kernel, can be adjusted to needs. Thanks to the fact that it is a system with GPL there is a possibility to compile a kernel optimized according to specific tasks. For example, for the built-in systems the kernel must be the smallest possible. For the counting systems the kernel is to use the server hardware architecture in the most efficient way. Apart from so specific situations in the administrator's practice the modules supporting specific hardware (e.g. hardware RAID) happen not to be contained in the kernel. In this situation it is necessary to compile the module to the kernel.
The process of installing and configuring the Slackware distribution is presented here, step by step. Starting from partitioning, configuring the time zone up to setting up passwords. As a result, you will get ready to use operating system.
Apparently Delphic oracle believes that "in Linux everything is a file". However, some people say that Linux is a primitive model of file permissions. Yes, it is very simple, but we invite you to read the information advanced attributes and properties of the kernel.
Data loss is equal to the loss of money by the administrator, and sometimes administrator gets fired. Methods of use of redundant disks have been systematized for a very long time and practically it is not acceptable for the admin not to know and understand the concepts of disk redundancy.
A description of Netflow mechanism implementation in the Linux system on the basis of the ntop program and the nProbe probe. The ntop program is an application doing the tasks of the network probe enabling visualization of using the network. The application work is similar to the work of the popular top application showing the work of processes in the system.
Keywords: ntop, nProbe, probe NetFlow, flow statistics, network analysis
The micro-course presents subjects connected with configuration of the Rsyslog server, its installation and configuration. Rsyslog is currently the main mechanism of supporting system events in Linux distributions. This program is compatible with the older syslogd system both on the architecture level and the configuration file.
Keywords: rsyslog, log systemowy, /etc/rsyslog.conf, modload, template, omnmp, ommysql, ommail, imudp, imtcp
As in every system, in the Linux system one of the most important support elements is the file system. It is used both for storing user data and for storing system files. The micro-course describes the most popular programs for supporting and modifying the partition table of the hard drive.
Problems with starting the system happen relatively less often than other kinds, yet they are severe. If the system is running, one of its parts is usually functioning. If Linux is not running, the problem is wholistic and so is the user irritation. Knowledge about the next steps of starting the system, loading the bootloader and its correct configuration in such situations becomes necessary. It often turns out that information about running the system was omitted in the process of learning how to administrate Linux. This micro-course is to show the process of booting the server with the Linux system.
Midnigt Commander is inspired by his great precursor, Norton Commander. This program, in time when DOS was the king, was installed on most computers. It's just very comfortable. And in addition it allows inexperienced users to easily navigate through the system of files.
The micro-course describes the way of creating the DEB packet. The simplest method is creating manually all necessary files making the packet and using the dpkg-deb command. This method of creating a packet requires making according structure files. To automate these tasks you can use the debhelper and the dh_make. In this micro-course you can find example procedures used for this purpose.
The micro-course presents types of backup copies used (a full copy, a growth copy, differential copy) and strategies used. Moreover, it describes example solutions of network systems for creating backup copies used in Linux systems.
Keywords: copy, diffrentia, full backup, Hanoi tower, GFS, backup mechanisms, tar, dd, automatization
It happens many times that the administrator feels that the system works slowly and standard commands checking the load of the system do not show anything. The only solution in this case is analyzing particular computer elements for efficiency. Three elements are usually checked – the process, the hard drive and the input/output system. The system can be loaded more so that the tests are effective. An example of such mechanism is the stress program. All these elements were described in this course.
The micro-course describes the most popular server of HTTP which is the free Apache server. It shows the history of the system, the architecture of the server work, and the way to install it. The micro-course is necessary if you want to implement the WWW server.
Keywords: apache, httpd, httpd.conf
The micro-course describes the most popular in the Linux system way of supporting resources shared in the Microsoft Windows network. This possibility is provided by the Samba program packet. It enables both sharing data contained in the Linux system partition with work stations with Microsoft Windows systems and their support of printers supported by Linux servers. Another function is the support of authorization for Linux users on the basis of data contained in the Active Directory system.
Keywords: SAMBA, smbd, CIFS, SMB, samba-tools, smb.conf
The course covers the operations of the transport layer of the ISO / OSI model. TCP and UDP protocols are presented. Knowledge about the functioning of the TCP and UDP protocols is very important for the construction of the firewalls and security systems (eg. IDS, UTM). In addition, many network problems can be detected by tracking the contents of the packet headers of TCP and UDP protocols. Consequently packet capturing is discussed on the basis of the simplest sniffer - tcpdump program. The course also shows information given by netstat program - included in both MS Windows and Linux systems.
Every Internet user knows how important electronic mail is. The role of the administrator is securing the mail server against possible attacks. This micro-course describes the basics of installation, configuration and managing the Qmail electronic mail server. The server was created as a safe alternative to the SMTP Sendmail server.
Keywords: qmail, smtp, /var/qmail/alias, alias, /var/qmail/control
In some cases the proxy server should be invisible to users. Therefore, you should use the transparent mode. In this configuration the Squid server gets and buffers all queries from all hosts in the local network. To configure the system in this way you should modify the mechanism of translating addresses. You can get information about how to do it from this course.
Keywords: squid, iptables, nat, transparent proxy, transparent proxy server
The micro-course describes the way of starting the system using a network and the PXE mechanism. This system is used for building diskless working stations which are downloaded from the net by all necessary files.
Keywords: PXE, boot, netboot, tftp
Rich support of protocols and cryptographic algorithms in the Linux system enabled creation of many tools using them. Some of the most popular tools are programs for encoding disks or partitions. In this micro-course there are the main procedures of encoding disks and partitions used in administrating this operating system.
Implementing an IT system in a small company, installing the ISC BIND server is pointless. In many cases simple solutions integrating a few protocols are enough. An example of such a solution is the DNSmasq program. The micro-course describes the architecture of this program, the installation of the program, an example configuration and useful configuration options.
In this part of the course we will present the basics of computer networks. We will introduce the concepts of LAN, MAN, WAN, Internet, Intranet, Extranet. We will present the differences between the physical topology and logical one. Network Administrators use the layered model called ISO/OSI and/or TCP/IP model. This part of the course will give you a reason to use the models.
Słowa kluczowe: LAN, MAN,WAN, Internet, Intranet, Extranet, ISO/OSI, TCP/IP, star, bus, ring, layer, physical, data link, network, transport, session, presentation, aplication
Convenience is the basic idea of structural network cable system. One should create such a network, for anybody to connect to anywhere in the building. This micro-course introduces the reader to the concept of designing of structural cabling systems. We discuss the most important rules that the designer/installer must follow when building a network. The course provides also the practical knowledge necessary for the installer to realize the project.
This micro-course gives basic information on the ways of creating encoded connections and technologies used for this purpose such as IpSec or OpenVPN.
Keywords: vpnc, Cisco VPN, klient Cisco VPN, ipsec, openssl, OpenVPN
The micro-course shows the way of using the iproute2 packet in the Linux system. It is a modern approach to the network management mechanism in new Linux system kernels. Thanks to this packet the kernel does not have to be limited only to one routing table. From the ip application level you can manage the Ethernet, IP or the TCP layers.
Keywords: ip, ip addr, ip route, ip link, ip neigh, ip rule
Documentation vanished and the server should be extended. How should you check what is inside the box? What hardware is being used? The micro-course presents information usually contained in most frequently used files with information about the system status from the /proc directory. There are short descriptions of logs saved by the Linux kernel while booting. There is a presentation of a very useful interface to the DMI (Desktop Management Interface) system allowing to check the model of the motherboard or the RAM chipset producer. And the best of all are the programs for testing efficiency of hard drives.
The administrator of the Linux system to make work easier often creates their own script whose role is automating tasks. However, the script without variables would only be an ordinary sequence of commands without a possibility to steer them. This micro-course describes the basics of how to use variables as well as replace them with values and how to delete them.