Wireless Network Server
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Wireless network server Contents Problem statement................................................................................................................................................3 Preliminary observation......................................................................................................................................4 Hardware................................................................................................................................................................4 System installation and disk layout..................................................................................................................7 Basic server configuration..................................................................................................................................8 Setting the system domain name..................................................................................................................8 Disabling IPv6....................................................................................................................................................8 Disabling Magic SysRq.....................................................................................................................................9 Creation of the users........................................................................................................................................9 Configuring access control lists...................................................................................................................11 Disabling unnecessary services..................................................................................................................12 Configuring the list of repositories............................................................................................................14 Installing auxiliary software.......................................................................................................................14 Configuring network..........................................................................................................................................15 Network interfaces confuguration.............................................................................................................15 Routing..............................................................................................................................................................17 Network bandwidth management.............................................................................................................19 Wireless network setup.....................................................................................................................................20 Managing a wireless network card............................................................................................................21 Configuring a software access point..........................................................................................................24 Automatic changing of the access point password................................................................................26 Fail protection (auto-resume)......................................................................................................................27 Verification of performance and stability................................................................................................27 DNS/DHCP service...............................................................................................................................................29 Configuration..................................................................................................................................................29 Fail protection (auto-resume)......................................................................................................................32 Verification of performance and stability................................................................................................33 Network time service (ntp)...............................................................................................................................34 Configuration..................................................................................................................................................34 Fail protection (auto-resume)......................................................................................................................38 Verification of performance and stability................................................................................................38 Installing and configuring ssh..........................................................................................................................39 Configuration..................................................................................................................................................39 1 Fail protection (auto-resume)......................................................................................................................41 Verification of performance and stability................................................................................................41 About additional services..................................................................................................................................42 Password protection (fail2ban)...................................................................................................................42 Log rotation (logrotate).................................................................................................................................43 Network time service (ntp)..........................................................................................................................43 Mail service......................................................................................................................................................43 Application software..........................................................................................................................................45 Application software Suite and graphical environment......................................................................45 Automatic restoration of interface and program settings....................................................................46 Displaying the current password...............................................................................................................47 Automatic system shutdown.......................................................................................................................47 Installing and configuring the network filter (nftables)............................................................................47 Network environment and potential threats..........................................................................................47 The structure of the network filter............................................................................................................49 Starting and checking the network filter..................................................................................................50 Completing the installation...............................................................................................................................60 Using the server...................................................................................................................................................60 Login procedure.............................................................................................................................................60 Hardware health monitoring......................................................................................................................61 Changing the external domain name server...........................................................................................62 Getting the current list of client devices...................................................................................................63 Notes on connecting clients.........................................................................................................................64 2 Problem statement It is needed to create a school wireless subnet server on the hardware base of the Lenovo g560 laptop according to the following network diagram: Figure 1: Network fragment This diagram shows the part of the school's network that is visible to the wireless network server (server.wifi.school34), indicates domain names and ipv4 addresses of some nodes. Most of the network is hidden because it should not be visible to either the wireless network clients or the server itself. The figure also shows a virtualization server that serves the service.school34 domain. On the basis of this server a number of virtual machines are deployed to provide different network services to clients of the school's network. The core of the school's network includes the AVERS automated information system (AIS AVERS further in this document) server and the system administrator's computer. The server must provide to clients a wireless transmission environment using an encrypted channel and regularly change the password to access it. The wireless network server must provide DHCP service for client devices on its wireless interface, supporting