From owner-svn-doc-projects@FreeBSD.ORG Mon May 20 13:44:27 2013 Return-Path: Delivered-To: svn-doc-projects@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 554DA369; Mon, 20 May 2013 13:44:27 +0000 (UTC) (envelope-from dru@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) by mx1.freebsd.org (Postfix) with ESMTP id 4692DA11; Mon, 20 May 2013 13:44:27 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.6/8.14.6) with ESMTP id r4KDiRhJ093578; Mon, 20 May 2013 13:44:27 GMT (envelope-from dru@svn.freebsd.org) Received: (from dru@localhost) by svn.freebsd.org (8.14.6/8.14.5/Submit) id r4KDiRQN093577; Mon, 20 May 2013 13:44:27 GMT (envelope-from dru@svn.freebsd.org) Message-Id: <201305201344.r4KDiRQN093577@svn.freebsd.org> From: Dru Lavigne Date: Mon, 20 May 2013 13:44:27 +0000 (UTC) To: doc-committers@freebsd.org, svn-doc-projects@freebsd.org Subject: svn commit: r41698 - projects/ISBN_1-57176-407-0/en_US.ISO8859-1/books/handbook/advanced-networking X-SVN-Group: doc-projects MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-doc-projects@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: SVN commit messages for doc projects trees List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 May 2013 13:44:27 -0000 Author: dru Date: Mon May 20 13:44:26 2013 New Revision: 41698 URL: http://svnweb.freebsd.org/changeset/doc/41698 Log: White space fix only. Translators can ignore. Approved by: mentors (implicit) Modified: projects/ISBN_1-57176-407-0/en_US.ISO8859-1/books/handbook/advanced-networking/chapter.xml Modified: projects/ISBN_1-57176-407-0/en_US.ISO8859-1/books/handbook/advanced-networking/chapter.xml ============================================================================== --- projects/ISBN_1-57176-407-0/en_US.ISO8859-1/books/handbook/advanced-networking/chapter.xml Mon May 20 12:50:10 2013 (r41697) +++ projects/ISBN_1-57176-407-0/en_US.ISO8859-1/books/handbook/advanced-networking/chapter.xml Mon May 20 13:44:26 2013 (r41698) @@ -46,7 +46,8 @@ - How to set up IPv6 on a &os; machine. + How to set up IPv6 on a &os; + machine. @@ -54,9 +55,9 @@ - How to enable and utilize the features of the - Common Address Redundancy Protocol - (CARP) in &os;. + How to enable and utilize the features of the Common + Address Redundancy Protocol (CARP) in + &os;. @@ -78,8 +79,8 @@ - Know how to install additional third-party - software (). + Know how to install additional third-party software + (). @@ -107,10 +108,10 @@ one to the other. This is called routing. A route is a defined pair of addresses: a destination and a - gateway. The pair indicates that when - trying to get to this destination, - communicate through this gateway. There - are three types of destinations: individual hosts, subnets, and + gateway. The pair indicates that when trying + to get to this destination, communicate + through this gateway. There are three + types of destinations: individual hosts, subnets, and default. The default route is used if none of the other routes apply. There are also three types of gateways: individual hosts, interfaces (also called @@ -139,9 +140,8 @@ host2.example.com link#1 UC 224 link#1 UC 0 0 default route - The first two lines specify the default route, - described in more detail in - , + The first two lines specify the default route, described + in more detail in , and the localhost route. loopback device @@ -156,46 +156,41 @@ host2.example.com link#1 UC Ethernet MAC address - The addresses beginning - with 0:e0: are Ethernet - hardware addresses, also known as MAC - addresses. - &os; will automatically identify any hosts, - test0 in the example, on the local Ethernet - and add a route for that host over the - Ethernet interface, ed0. This type - of route has a timeout, seen in the Expire - column, which is used if - the host does not respond in a specific amount of time. When - this happens, the - route to this host will be automatically deleted. These hosts - are identified using the Routing - Information Protocol (RIP), which - calculates routes to local hosts - based upon a shortest path determination. + The addresses beginning with 0:e0: are Ethernet hardware addresses, + also known as MAC addresses. &os; will + automatically identify any hosts, test0 in + the example, on the local Ethernet and add a route for that + host over the Ethernet interface, + ed0. This type of route has a + timeout, seen in the Expire column, which + is used if the host does not respond in a specific amount of + time. When this happens, the route to this host will be + automatically deleted. These hosts are identified using the + Routing Information Protocol (RIP), which + calculates routes to local hosts based upon a shortest path + determination. subnet &os; will add subnet routes for the local subnet. 10.20.30.255 is the broadcast - address for the subnet - 10.20.30 and - example.com is the domain - name associated with that subnet. The designation + address for the subnet 10.20.30 + and example.com is the + domain name associated with that subnet. The designation link#1 refers to the first Ethernet card in the machine. - Local network hosts and local - subnets have their routes automatically configured by a - daemon called &man.routed.8;. If it is - not running, only routes which are statically defined + Local network hosts and local subnets have their routes + automatically configured by a daemon called &man.routed.8;. + If it is not running, only routes which are statically defined by the administrator will exist. The host1 line refers to the host - by its Ethernet address. Since it is the sending - host, &os; knows to use the loopback interface - (lo0) rather than - the Ethernet interface. + by its Ethernet address. Since it is the sending host, &os; + knows to use the loopback interface + (lo0) rather than the Ethernet + interface. The two host2 lines represent aliases which were created using &man.ifconfig.8;. The @@ -206,8 +201,8 @@ host2.example.com link#1 UC hosts on the local network will have a link#1 line for such routes. - The final line (destination subnet - 224) deals with + The final line (destination subnet 224) deals with multicasting. Finally, various attributes of each route can be seen in @@ -276,8 +271,8 @@ host2.example.com link#1 UC When the local system needs to make a connection to a remote host, it checks the routing table to determine if a known path exists. If the remote host falls into a subnet - that it knows how to reach, the system - checks to see if it can connect using that interface. + that it knows how to reach, the system checks to see if it + can connect using that interface. If all known paths fail, the system has one last option: the default route. This route is a special @@ -287,13 +282,13 @@ host2.example.com link#1 UC gateway is set to the system which has a direct connection to the Internet. - The default route for a machine - which itself is functioning as the gateway to the outside - world, will be the gateway machine at - the Internet Service Provider (ISP). + The default route for a machine which itself is + functioning as the gateway to the outside world, will be the + gateway machine at the Internet Service Provider + (ISP). - This example is a - common configuration for a default route: + This example is a common configuration for a default + route: @@ -311,12 +306,11 @@ host2.example.com link#1 UC Local1 is connected to an ISP using a PPP connection. This - PPP server is connected through - a local area network to another gateway computer through an - external interface to the ISP. + PPP server is connected through a local + area network to another gateway computer through an external + interface to the ISP. - The default routes for each machine will - be: + The default routes for each machine will be: @@ -347,29 +341,25 @@ host2.example.com link#1 UC A common question is Why is T1-GW configured as the default gateway for Local1, rather than the - ISP server it is - connected to?. + ISP server it is connected + to?. Since the PPP interface is using an - address on - the ISP's local network for the local side - of the connection, - routes for any other machines on the ISP's - local network will + address on the ISP's local network for + the local side of the connection, routes for any other + machines on the ISP's local network will be automatically generated. The system already knows how to reach the T1-GW machine, so there is no need for the intermediate step of sending traffic to the - ISP's - server. + ISP's server. - It is common to use the address - X.X.X.1 as the gateway address - for the local network. So, if the - local class C address space is + It is common to use the address X.X.X.1 as the gateway address for + the local network. So, if the local class C address space is 10.20.30 and the - ISP is using - 10.9.9, the default routes - would be: + ISP is using 10.9.9, the default routes would + be: @@ -395,8 +385,8 @@ host2.example.com link#1 UC The default route can be easily defined in /etc/rc.conf. In this example, on - Local2, add the following - line to /etc/rc.conf: + Local2, add the following line to + /etc/rc.conf: defaultrouter="10.20.30.1" @@ -414,17 +404,16 @@ host2.example.com link#1 UC dual homed hosts - A a dual-homed system - is a host which resides on two different networks. + A a dual-homed system is a host which resides on two + different networks. The dual-homed machine might have two Ethernet cards, each having an address on a separate subnet. Alternately, the - machine can have one Ethernet card and uses - &man.ifconfig.8; aliasing. The former is used if two - physically separate Ethernet networks are in use and the - latter - if there is one physical network segment, but two logically - separate subnets. + machine can have one Ethernet card and uses &man.ifconfig.8; + aliasing. The former is used if two physically separate + Ethernet networks are in use and the latter if there is one + physical network segment, but two logically separate + subnets. Either way, routing tables are set up so that each subnet knows that this machine is the defined gateway (inbound route) @@ -433,9 +422,9 @@ host2.example.com link#1 UC to implement packet filtering or firewall security in either or both directions. - For this machine to forward packets - between the two interfaces, &os; must be configured as a - router, as demonstrated in the next section. + For this machine to forward packets between the two + interfaces, &os; must be configured as a router, as + demonstrated in the next section. @@ -443,8 +432,8 @@ host2.example.com link#1 UC router - A network router is a system that forwards packets - from one interface to another. Internet standards and good + A network router is a system that forwards packets from + one interface to another. Internet standards and good engineering practice prevent the &os; Project from enabling this by default in &os;. This feature can be enabled by changing the following variable to YES in @@ -454,17 +443,17 @@ host2.example.com link#1 UC This option will set the &man.sysctl.8; variable net.inet.ip.forwarding to - 1. To stop routing, - reset this to 0. + 1. To stop routing, reset this to + 0. BGP RIP OSPF The new router will need routes to know where to send the - traffic. If the network is simple enough, static - routes can be used. &os; comes with the standard BSD routing - daemon &man.routed.8;, which speaks RIP - versions 1 and 2, and IRDP. Support for + traffic. If the network is simple enough, static routes can + be used. &os; comes with the standard BSD routing daemon + &man.routed.8;, which speaks RIP versions + 1 and 2, and IRDP. Support for BGPv4, OSPFv2, and other sophisticated routing protocols is available with the net/zebra package or @@ -523,16 +512,14 @@ host2.example.com link#1 UC In this scenario, RouterA is a &os; machine that is acting as a router to the rest of the - Internet. It has a default route set to - 10.0.0.1 which allows it to + Internet. It has a default route set to 10.0.0.1 which allows it to connect with the outside world. RouterB is - already configured properly as it - uses - 192.168.1.1 as the - gateway. + already configured properly as it uses 192.168.1.1 as the gateway. - The routing table on - RouterA looks something like this: + The routing table on RouterA looks + something like this: &prompt.user; netstat -nr Routing tables @@ -545,13 +532,11 @@ default 10.0.0.1 UG 192.168.1.0/24 link#2 UC 0 0 xl1 With the current routing table, RouterA - cannot reach Internal Net 2 as it does not - have a route for + cannot reach Internal Net 2 as it does not have a route for 192.168.2.0/24. The - following - command adds the Internal Net 2 network to - RouterA's routing table using - 192.168.1.2 as the next + following command adds the Internal Net 2 network to + RouterA's routing table using 192.168.1.2 as the next hop: &prompt.root; route add -net 192.168.2.0/24 192.168.1.2 @@ -564,11 +549,11 @@ default 10.0.0.1 UG Persistent Configuration - The above example configures a static - route on a running system. However, the - routing information will not persist if the &os; system - reboots. Persistent static routes can be - entered in /etc/rc.conf: + The above example configures a static route on a + running system. However, the routing information will not + persist if the &os; system reboots. Persistent static + routes can be entered in + /etc/rc.conf: # Add Internal Net 2 as a static route static_routes="internalnet2" @@ -576,23 +561,21 @@ route_internalnet2="-net 192.168.2.0/24 The static_routes configuration variable is a list of strings separated by a space, where - each - string references a route name. This example - only has one string in static_routes, + each string references a route name. This example only + has one string in static_routes, internalnet2. The variable route_internalnet2 - contains all of the configuration parameters - to &man.route.8;. This example is equivalent - to the command: + contains all of the configuration parameters to + &man.route.8;. This example is equivalen to the + command: &prompt.root; route add -net 192.168.2.0/24 192.168.1.2 Using more than one string in - static_routes creates - multiple static routes. The following shows an - example of adding static routes for the - 192.168.0.0/24 and - 192.168.1.0/24 + static_routes creates multiple static + routes. The following shows an example of adding static + routes for the 192.168.0.0/24 + and 192.168.1.0/24 networks: static_routes="net1 net2" @@ -610,16 +593,14 @@ route_net2="-net 192.168.1.0/24 192.168. site. But how do external sites know to send their packets to the network's ISP? - There is a system - that keeps track of all assigned address spaces - and defines their point of connection to the Internet - backbone, or the main trunk - lines that carry Internet traffic across the country and - around the world. Each backbone machine has a copy of a - master set of tables, which direct traffic for a particular - network to a specific backbone carrier, and from there down - the chain of service providers until it reaches your - network. + There is a system that keeps track of all assigned + address spaces and defines their point of connection to the + Internet backbone, or the main trunk lines that carry Internet + traffic across the country and around the world. Each + backbone machine has a copy of a master set of tables, which + direct traffic for a particular network to a specific + backbone carrier, and from there down the chain of service + providers until it reaches your network. It is the task of the service provider to advertise to the backbone sites that they are the point of connection, and @@ -637,17 +618,16 @@ route_net2="-net 192.168.1.0/24 192.168. Sometimes, there is a problem with routing propagation and some sites are unable to connect. Perhaps the most useful command for trying to figure out where routing is - breaking down is &man.traceroute.8;. It is - useful when &man.ping.8; fails. + breaking down is &man.traceroute.8;. It is useful when + &man.ping.8; fails. When using &man.traceroute.8;, include the name of the - remote host to connect to. The output will show the - gateway hosts along the path of the attempt, eventually either + remote host to connect to. The output will show the gateway + hosts along the path of the attempt, eventually either reaching the target host, or terminating because of a lack of connection. - For more information, refer to - &man.traceroute.8;. + For more information, refer to &man.traceroute.8;. @@ -661,17 +641,15 @@ route_net2="-net 192.168.1.0/24 192.168. MROUTING &os; natively supports both multicast applications and - multicast - routing. Multicast applications do not require any + multicast routing. Multicast applications do not require any special configuration of &os;; as applications will generally - run out of the box. Multicast routing - requires that support be compiled into a custom kernel: + run out of the box. Multicast routing requires that support + be compiled into a custom kernel: options MROUTING - The multicast routing daemon, &man.mrouted.8;, - must be configured to set up tunnels and - DVMRP via + The multicast routing daemon, &man.mrouted.8;, must be + configured to set up tunnels and DVMRP via /etc/mrouted.conf. More details on multicast configuration may be found in &man.mrouted.8;. @@ -682,8 +660,8 @@ route_net2="-net 192.168.1.0/24 192.168. which has largely been replaced by &man.pim.4; in many multicast installations. &man.mrouted.8; and the related &man.map-mbone.8; and &man.mrinfo.8; utilities are available - in the &os; Ports Collection as - net/mrouted. + in the &os; Ports Collection as net/mrouted. @@ -729,96 +707,83 @@ route_net2="-net 192.168.1.0/24 192.168. a master with all the other stations associating to it, the network is known as a BSS, and the master - station is termed an - access point (AP). In a - BSS, all communication passes through + station is termed an access point (AP). + In a BSS, all communication passes through the AP; even when one station wants to - communicate with - another wireless station, messages must go through the - AP. In - the second form of network, there is no master and stations - communicate directly. This form of network is termed an - IBSS - and is commonly known as an - ad-hoc network. + communicate with another wireless station, messages must go + through the AP. In the second form of + network, there is no master and stations communicate directly. + This form of network is termed an IBSS + and is commonly known as an ad-hoc + network. 802.11 networks were first deployed in the 2.4GHz band using protocols defined by the &ieee; 802.11 and 802.11b standard. These specifications include the operating frequencies and the MAC layer - characteristics, including framing and - transmission rates, as communication can occur at various - rates. Later, the 802.11a standard defined operation in the - 5GHz band, including different signaling mechanisms and - higher transmission rates. Still later, the 802.11g standard - defined the use of 802.11a signaling and - transmission mechanisms in the 2.4GHz band in such a way as to - be backwards compatible with 802.11b networks. + characteristics, including framing and transmission rates, + as communication can occur at various rates. Later, the + 802.11a standard defined operation in the 5GHz band, including + different signaling mechanisms and higher transmission rates. + Still later, the 802.11g standard defined the use of 802.11a + signaling and transmission mechanisms in the 2.4GHz band in + such a way as to be backwards compatible with 802.11b + networks. Separate from the underlying transmission techniques, 802.11 networks have a variety of security mechanisms. The original 802.11 specifications defined a simple security protocol called WEP. This protocol uses a - fixed pre-shared key - and the RC4 cryptographic cipher to encode data transmitted on - a network. Stations must all agree on the fixed key in order - to communicate. This scheme was shown to be easily broken and - is now rarely used except to discourage transient users from - joining networks. Current security practice is given by the - &ieee; 802.11i specification that defines new cryptographic - ciphers and an additional protocol to authenticate stations to - an access point and exchange keys for data - communication. Cryptographic keys are periodically - refreshed and there are mechanisms for detecting - and countering intrusion attempts. Another + fixed pre-shared key and the RC4 cryptographic cipher to + encode data transmitted on a network. Stations must all + agree on the fixed key in order to communicate. This scheme + was shown to be easily broken and is now rarely used except + to discourage transient users from joining networks. Current + security practice is given by the &ieee; 802.11i specification + that defines new cryptographic ciphers and an additional + protocol to authenticate stations to an access point and + exchange keys for data communication. Cryptographic keys + are periodically refreshed and there are mechanisms for + detecting and countering intrusion attempts. Another security protocol specification commonly used in wireless networks is termed WPA, which was a - precursor to 802.11i. WPA - specifies a subset of - the requirements found in 802.11i and is designed for - implementation on legacy hardware. Specifically, - WPA requires - only the TKIP cipher that is derived from - the original WEP - cipher. 802.11i permits use of TKIP but - also requires support - for a stronger cipher, AES-CCM, for encrypting data. The - AES - cipher was not required in WPA because it - was deemed too + precursor to 802.11i. WPA specifies a + subset of the requirements found in 802.11i and is designed + for implementation on legacy hardware. Specifically, + WPA requires only the + TKIP cipher that is derived from the + original WEP cipher. 802.11i permits use + of TKIP but also requires support for a + stronger cipher, AES-CCM, for encrypting data. The + AES cipher was not required in + WPA because it was deemed too computationally costly to be implemented on legacy hardware. - The other - standard to be aware of is 802.11e. It defines + The other standard to be aware of is 802.11e. It defines protocols for deploying multimedia applications, such as streaming video and voice over IP (VoIP), - in - an 802.11 network. - Like 802.11i, 802.11e also has a precursor specification - termed WME (later renamed - WMM) that has been defined by an + in an 802.11 network. Like 802.11i, 802.11e also has a + precursor specification termed WME (later + renamed WMM) that has been defined by an industry group as a subset of 802.11e that can be deployed now to enable multimedia applications while waiting for the final ratification of 802.11e. The most important thing to know about 802.11e and WME/WMM is that it - enables prioritized - traffic over a wireless network through Quality of Service - (QoS) protocols and enhanced media access - protocols. Proper - implementation of these protocols enables high speed bursting - of data and prioritized traffic flow. - - &os; supports networks that operate - using 802.11a, 802.11b, and 802.11g. The - WPA and 802.11i + enables prioritized traffic over a wireless network through + Quality of Service (QoS) protocols and + enhanced media access protocols. Proper implementation of + these protocols enables high speed bursting of data and + prioritized traffic flow. + + &os; supports networks that operate using 802.11a, + 802.11b, and 802.11g. The WPA and 802.11i security protocols are likewise supported (in conjunction with any of 11a, 11b, and 11g) and QoS and - traffic prioritization - required by the WME/WMM - protocols are supported for a limited - set of wireless devices. + traffic prioritization required by the + WME/WMM protocols are + supported for a limited set of wireless devices. @@ -827,65 +792,58 @@ route_net2="-net 192.168.1.0/24 192.168. Kernel Configuration - To use wireless networking, a wireless - networking card is needed and the kernel needs to be - configured with the + To use wireless networking, a wireless networking card + is needed and the kernel needs to be configured with the appropriate wireless networking support. The kernel is separated into multiple modules so that only the required - support needs to be - configured. + support needs to be configured. The most commonly used wireless devices are those that use parts made - by - Atheros. These devices are supported by &man.ath.4; + by Atheros. These devices are supported by &man.ath.4; and require the following line to be added to /boot/loader.conf: if_ath_load="YES" The Atheros driver is split up into three separate - pieces: the driver (&man.ath.4;), the hardware - support layer that handles chip-specific functions + pieces: the driver (&man.ath.4;), the hardware support + layer that handles chip-specific functions (&man.ath.hal.4;), and an algorithm for selecting the - rate for transmitting frames. - When this support is loaded as - kernel modules, any dependencies are automatically handled. - To load support for a different type of wireless device, - specify the module for that device. This example is for - devices based on the Intersil Prism parts (&man.wi.4;) - driver: + rate for transmitting frames. When this support is loaded + as kernel modules, any dependencies are automatically + handled. To load support for a different type of wireless + device, specify the module for that device. This example + is for devices based on the Intersil Prism parts + (&man.wi.4;) driver: if_wi_load="YES" - The examples in this section use an - &man.ath.4; device and the device name in the examples - must - be changed according to the configuration. A list of + The examples in this section use an &man.ath.4; + device and the device name in the examples must be + changed according to the configuration. A list of available wireless drivers and supported adapters can be found in the &os; Hardware Notes, available on the Release Information page of the &os; website. If a native &os; driver for the wireless device does not - exist, it may be possible to use the &windows; - driver with the help of the - NDIS driver + exist, it may be possible to use the &windows; driver + with the help of the NDIS driver wrapper. - In addition, the modules that implement - cryptographic support for the security protocols - to use must be loaded. These are intended to be dynamically - loaded on - demand by the &man.wlan.4; module, but for now they must be - manually configured. The following modules are available: + In addition, the modules that implement cryptographic + support for the security protocols to use must be loaded. + These are intended to be dynamically loaded on demand by + the &man.wlan.4; module, but for now they must be manually + configured. The following modules are available: &man.wlan.wep.4;, &man.wlan.ccmp.4;, and &man.wlan.tkip.4;. The &man.wlan.ccmp.4; and &man.wlan.tkip.4; drivers are only needed when using the WPA or - 802.11i - security protocols. If the network does not use + 802.11i security protocols. If the network does not use encryption, &man.wlan.wep.4; support is not needed. To load these modules at boot time, add the following lines to /boot/loader.conf: @@ -895,17 +853,15 @@ wlan_ccmp_load="YES" wlan_tkip_load="YES" Once this information has been added to - /boot/loader.conf, reboot - the &os; box. Alternately, - load the modules by hand using + /boot/loader.conf, reboot the &os; + box. Alternately, load the modules by hand using &man.kldload.8;. For users who do not want to use modules, it is - possible to - compile these drivers into the kernel by adding the - following lines to a custom kernel configuration - file: + possible to compile these drivers into the kernel by + adding the following lines to a custom kernel + configuration file: device wlan # 802.11 support device wlan_wep # 802.11 WEP support @@ -922,10 +878,8 @@ device ath_rate_sample # SampleRate tx machine. - Information - about the wireless device should appear in the boot - messages, like - this: + Information about the wireless device should appear + in the boot messages, like this: ath0: <Atheros 5212> mem 0x88000000-0x8800ffff irq 11 at device 0.0 on cardbus1 ath0: [ITHREAD] @@ -937,12 +891,11 @@ ath0: AR2413 mac 7.9 RF2413 phy 4.5Infrastructure Mode Infrastructure (BSS) mode is the - mode that is - typically used. In this mode, a number of wireless access - points are connected to a wired network. Each wireless - network has its own name, called the SSID. - Wireless clients connect to the wireless access - points. + mode that is typically used. In this mode, a number of + wireless access points are connected to a wired network. + Each wireless network has its own name, called the + SSID. Wireless clients connect to the + wireless access points. &os; Clients @@ -950,12 +903,11 @@ ath0: AR2413 mac 7.9 RF2413 phy 4.5 How to Find Access Points - To scan for available networks, use - &man.ifconfig.8;. This request may - take a few moments to complete as it requires the - system to switch to each available wireless frequency and - probe for available access points. Only the superuser - can initiate a scan: + To scan for available networks, use &man.ifconfig.8;. + This request may take a few moments to complete as it + requires the system to switch to each available wireless + frequency and probe for available access points. Only + the superuser can initiate a scan: &prompt.root; ifconfig wlan0 create wlandev ath0 &prompt.root; ifconfig wlan0 up scan @@ -964,20 +916,20 @@ dlinkap 00:13:46:49:41:76 11 freebsdap 00:11:95:c3:0d:ac 1 54M -83:96 100 EPS WPA - The interface must be - before it can scan. Subsequent scan requests do not - require the interface to be marked as up again. + The interface must be before + it can scan. Subsequent scan requests do not require + the interface to be marked as up again. The output of a scan request lists each - BSS/IBSS - network found. Besides listing the name of the network, - the SSID, the output also shows the + BSS/IBSS network + found. Besides listing the name of the network, the + SSID, the output also shows the BSSID, which is the - MAC address of the - access point. The CAPS field - identifies the type of each network and the capabilities - of the stations operating there: + MAC address of the access point. The + CAPS field identifies the type of + each network and the capabilities of the stations + operating there: Station Capability Codes @@ -1003,18 +955,18 @@ freebsdap 00:11:95:c3:0d:ac 1 I IBSS/ad-hoc network. - Indicates that the - station is part of an ad-hoc network rather than - an ESS network. + Indicates that the station is part of an ad-hoc + network rather than an ESS + network. P - Privacy. Encryption is required - for all data frames exchanged within the - BSS - using cryptographic means such as - WEP, TKIP or + Privacy. Encryption is required for all + data frames exchanged within the + BSS using cryptographic means + such as WEP, + TKIP or AES-CCMP. @@ -1022,10 +974,9 @@ freebsdap 00:11:95:c3:0d:ac 1 SShort Preamble. Indicates that the network is using short preambles, defined in 802.11b High - Rate/DSSS PHY, and utilizes a 56 bit - sync field rather than the 128 bit - field used in - long preamble mode. + Rate/DSSS PHY, and utilizes a 56 bit sync field + rather than the 128 bit field used in long + preamble mode. @@ -1056,15 +1007,14 @@ freebsdap 00:11:95:c3:0d:ac 1 This section provides a simple example of how to make the wireless network adapter work in &os; without encryption. Once familiar with these concepts, it is - strongly recommend to use - WPA to set up + strongly recommend to use WPA to set up the wireless network. There are three basic steps to configure a wireless network: select an access point, authenticate the station, and configure an IP address. - The following - sections discuss each step. + The following sections discuss each step. Selecting an Access Point @@ -1072,15 +1022,14 @@ freebsdap 00:11:95:c3:0d:ac 1 Most of the time, it is sufficient to let the system choose an access point using the builtin heuristics. This is the default behaviour when an interface is - marked as - up or it is listed in + marked as up or it is listed in /etc/rc.conf: wlans_ath0="wlan0" ifconfig_wlan0="DHCP" - If there are multiple access points, - a specific one can be selected by its + If there are multiple access points, a specific + one can be selected by its SSID: wlans_ath0="wlan0" @@ -1088,11 +1037,10 @@ ifconfig_wlan0="ssid your_s In an environment where there are multiple access points with the same SSID, which - is often done to simplify - roaming, it may be necessary to associate to one - specific device. In this case, the - BSSID of the access point can - be specified, with or without the + is often done to simplify roaming, it may be necessary + to associate to one specific device. In this case, the + BSSID of the access point can be + specified, with or without the SSID: wlans_ath0="wlan0" @@ -1100,8 +1048,7 @@ ifconfig_wlan0="ssid your_s There are other ways to constrain the choice of an access point, such as limiting the set of frequencies - the - system will scan on. This may be useful for a + the system will scan on. This may be useful for a multi-band wireless card as scanning all the possible channels can be time-consuming. To limit operation to a specific band, use the @@ -1111,13 +1058,11 @@ ifconfig_wlan0="ssid your_s ifconfig_wlan0="mode 11g ssid your_ssid_here DHCP" This example will force the card to operate in - 802.11g, which is - defined only for 2.4GHz frequencies so any 5GHz channels - will not be considered. This can also be achieved with - the + 802.11g, which is defined only for 2.4GHz frequencies + so any 5GHz channels will not be considered. This can + also be achieved witt the parameter, which locks - operation to - one specific frequency, and the + operation to one specific frequency, and the parameter, to specify a list of channels for scanning. More information about these parameters can be found in &man.ifconfig.8;. @@ -1129,49 +1074,42 @@ ifconfig_wlan0="mode 11gOnce an access point is selected, the station needs to authenticate before it can pass data. Authentication can happen in several ways. The most - common scheme, open authentication, - allows any station to join the network and communicate. - This is the authentication to use for test - purposes the first time a wireless network is setup. - Other schemes require cryptographic handshakes to be - completed before data traffic can flow, either using - pre-shared keys or secrets, or more complex schemes that - involve backend services such as - RADIUS. - Open authentication is the default - setting. The next most common setup is - WPA-PSK, also - known - as WPA Personal, which is described - in RADIUS. Open + authentication is the default setting. The next most + common setup is WPA-PSK, also + known as WPA Personal, which is + described in . If using an &apple; &airport; Extreme base - station for an access point, - shared-key authentication together with a - WEP key needs to be configured. - This can be configured in + station for an access point, shared-key authentication + together with a WEP key needs to + be configured. This can be configured in /etc/rc.conf or by using *** DIFF OUTPUT TRUNCATED AT 1000 LINES ***