CCNA4_M1_Scaling_IP_Address (1130785)
Текст из файла
CCNA – Semester4Module 1Scaling IP AddressObjectives• Scaling networks with NAT and PAT• Dynamic Host Configuration ProtocolScaling networks withNAT and PATIntroducing NAT• NAT is designed to conserve IP addresses and enablenetworks to use private IP addresses on internalnetworks.• These private, internal addresses are translated toroutable, public addresses.NAT terms••••Inside local address – The IP address assigned to a host on the inside network (not alegitimate IP address-RFC 1918 private address).Inside global address – A legitimate IP address represents one or more inside local IPaddresses to the outside world.Outside local address – The IP address of an outside host as it is known to the hostson the inside network.Outside global address – The IP address assigned to a host on the outside network.The owner of the host assigns this address.Major NAT and PAT features• NAT translations can be used for a variety ofpurposes and can be either dynamically orstatically assigned.• Dynamic NAT is designed to map a private IPaddress to a public address.• Overloading, or Port Address Translation (PAT),maps multiple private IP addresses to a singlepublic IP address.• Realistically, the number of ports that can beassigned a single IP address is around 4000.Major NAT and PAT featuresNAT advantages• Eliminates reassigning each host a new IPaddress when changing to a new ISP.• Conserves addresses through application portlevel multiplexing.• Protects network security.• Reduce address overlap occurrence.NAT disadvantages• Translation introduces switching path delaysand processing overhead.• Loss of IP end-to-end traceability.• Certain application will not function with NATenabled.Cisco IOS NATConfigure static NATStatic translationConfigure dynamic NATConfigure dynamic NATConfigure dynamic NATDynamic NAT exampleConfigure PATClear NAT tableShow NAT translationTroubleshooting NAT and PAT configuration• Use the following steps to determine whether NAT isoperating as expected:– Based on the configuration, clearly define what NAT is supposed toachieve.– Verify that correct translations exist in the translation table.– Verify the translation is occurring by using show and debugcommands.– Review in detail what is happening to the packet and verify thatrouters have the correct routing information to move the packet along.Debug IP NATDynamic Host ConfigurationProtocolIntroducing DHCP• Dynamic Host Configuration Protocol (DHCP)works in a client/server mode.• DHCP enables DHCP clients on an IP network toobtain their configurations from a DHCP server.• Less work is involved in managing an IPnetwork when DHCP is used.• The DHCP protocol is described in RFC 2131.Easy IP• Cisco routers can use a Cisco IOS feature set,Easy IP, to offer an optional, full-featured DHCPserver.• Easy IP leases configurations for 24 hours bydefault.• The DHCP service is enabled by default onversions of Cisco IOS that support it.• To disable DHCP service, use the no service dhcpcommand.BOOTP and DHCP• Both protocols are client/server based and use UDPports 67 and 68.
Those ports are still known as BOOTPports.• The four basic IP parameters:––––IP addressGateway addressSubnet maskDNS server addressDHCP OperationDHCP Messages•••If the client detects thatthe address is alreadyin use on the localsegment it will send aDHCPDECLINEmessage and theprocess starts again.If the client received a DHCPNACK from the server aftersending the DHCPREQUEST, then it will restart the processagain.If the client no longer needs the IP address, the client sends aDHCPRELEASE message to the server.CISCO IOS DHCP• Cisco IOS DHCP server always checks to makesure that an address is not in use before theserver offers it to a client.• By default, router will issue 2 ICMP echorequests, or will ping, to a pool address beforesending the DHCPOFFER to a client.Configuring DHCPExcluding IPKey DHCP Server CommandsVerifying DHCP operation• To verify the operation of DHCP, the command showip dhcp binding can be used.• To verify that messages are being received or sentby the router, use the command show ip dhcp serverstatistics.Troubleshooting DHCPNetwork services• Remote clients will broadcast to locate serverswhile routers, by default, will not forward clientbroadcasts beyond their subnet.IP helper-address• Remote clients will broadcast to locate servers whilerouters, by default, will not forward client broadcastsbeyond their subnet.• When possible, administrators should use the ip helperaddress command to relay broadcast requests for thesekey UDP services.• By default, the ip helper-address command forwards thefollowing eight UDP services:––––––––TimeTACACSDNSBOOTP/DHCP ServerBOOTP/DHCP ClientTFTPNetBIOS Name ServiceNetBIOS datagram ServiceDHCP RelaySummary• NAT and PAT concepts and operation• NAT and PAT configuration andtroubleshooting• Comparison between DHCP and BOOTP• Cisco Router DHCP configuration• DHCP relay with ip helper-addressLab TopologyLab Requirements1.
NAT/PAT••Each Site use network address 10.x.0.0/16. Globaladdress is 172.20.x.0/28. Network connecting to Centeris 203.162.x.0/30.Configuring a static NAT mapping and dynamic NAT2. DHCP•Each Site use Router as a DHCP server to provide IPaddresses to department network.CCNA4 – Module1.
Характеристики
Тип файла PDF
PDF-формат наиболее широко используется для просмотра любого типа файлов на любом устройстве. В него можно сохранить документ, таблицы, презентацию, текст, чертежи, вычисления, графики и всё остальное, что можно показать на экране любого устройства. Именно его лучше всего использовать для печати.
Например, если Вам нужно распечатать чертёж из автокада, Вы сохраните чертёж на флешку, но будет ли автокад в пункте печати? А если будет, то нужная версия с нужными библиотеками? Именно для этого и нужен формат PDF - в нём точно будет показано верно вне зависимости от того, в какой программе создали PDF-файл и есть ли нужная программа для его просмотра.
![](https://s.studizba.com/z.php?f=/templates/si/i/noavatar.png&w=100&h=100&t=1"){kind=avatar}
