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Chapter 07 IP addressing services
Chapter 7: IP Addressing Services CCNA Exploration 4.0 Objectives DHCP Introducing DHCP • • • • • • Every device that connects to a network needs an IP address Network administrators assign static IP addresses to routers, servers, and other network devices whose locations (physical and logical) are not likely to change Network devices that are added, moved or changed (physical and logical) need new addresses Manual configuration is unwieldy dynamic configuration DHCP assigns IP addresses and other important network configuration information dynamically DHCP is an extremely useful and timesaving tool for network administrators Cisco router can be configured to provide DHCP services, called Easy IP DHCP Operation • • DHCP automatically dynamically assigns, or leases, an IP address from a pool of addresses for a limited period of time chosen by the server, or until the client tells the DHCP server that it no longer needs the address DHCP works in a client/server mode BOOTP and DHCP • • The Bootstrap Protocol (BOOTP), defined in RFC 951, is the predecessor of DHCP and shares some operational characteristics Both DHCP and BOOTP are client/server based and use UDP ports 67 and 68 DHCP Message Format DHCP Discovery and Offer Methods DHCP Discovery and Offer Methods Configuring a DHCP Server • Step Define a range of addresses that DHCP is not to allocate • Step Create the DHCP pool 10 Cisco IOS Dual Stack • • An integration method that allows a node to have connectivity to an IPv4 and IPv6 network simultaneously Each node has two protocol stacks with the configuration on the same interface or on multiple interfaces 74 Cisco IOS Dual Stack • • • • A dual-stack node chooses which stack to use based on the destination address of the packet New and modified applications take advantage of both IP layers A new application programming interface (API) has been defined to support IPv4 and IPv6 addresses and DNS requests Cisco IOS Release 12.2(2)T and later (with the appropriate feature set) are IPv6-ready 75 IPv6 Tunneling • Tunneling is an integration method in which an IPv6 packet is encapsulated within another protocol, such as IPv4 This method of encapsulation is IPv4: – Includes a 20-byte IPv4 header with no options and an IPv6 header and payload – Requires dual-stack routers 76 Manually Configured IPv6 Tunnel • Configured tunnels require: – Dual-stack endpoints – IPv4 and IPv6 addresses configured at each end 77 Routing Considerations with IPv6 • • • IPv6 uses longest prefix match routing An ISP aggregates all of the prefixes of its customers into a single prefix and announces the single prefix to the IPv6 Internet Conceptually, a router has three functional areas: – The control plane: handles the interaction of the router with the other network elements, providing the information needed to make decisions and control the overall router operation – The data plane: handles packet forwarding from one physical or logical interface to another – Enhanced services: include advanced features applied when forwarding data 78 Routing Considerations with IPv6 79 Routing Considerations with IPv6 • RIPNg Routing Protocol 80 Configuring IPv6 Addresses • • • • Enabling IPv6 on Cisco Routers: steps – Activate IPv6 traffic-forwarding on the router – Configure each interface that requires IPv6 By default, IPv6 traffic-forwarding is disabled on a Cisco router Use the global command ipv6 unicast-routing to activate IPv6 routing Use the ipv6 address command to configure a global IPv6 address 81 IPv6 Address Configuration Example 82 Cisco IOS IPv6 Name Resolution • • Define a static name for an IPv6 address using the ipv6 host name [port] ipv6-address1 [ipv6-address2 ipv6address4] command Specify the DNS server used by the router with the ip nameserver address command The address can be an IPv4 or IPv6 address You can specify up to six DNS servers with this command 83 Configure RIPng with IPv6 • Before configuring the router to run IPv6 RIP, globally enable IPv6 using the ipv6 unicast-routing global configuration command, and enable IPv6 on any interfaces on which IPv6 RIP is to be enabled 84 Configure RIPng with IPv6: Example 85 Verifying RIPng for IPv6 86 Troubleshooting RIPng for IPv6 • Activity 7.3.9.2 87 Summary 88 ... debug command: – debug ip packet detail 100 – debug ip dhcp server packet – debug ip dhcp server events Activity 7.1.8.4 29 Scaling Networks with NAT 30 Private and Public Addressing 31 What is... generally only translates IP addresses on a 1:1 correspondence between publicly exposed IP addresses and privately held IP addresses NAT overload modifies both the private IP address and port number... Cisco router can be configured to provide DHCP services, called Easy IP DHCP Operation • • DHCP automatically dynamically assigns, or leases, an IP address from a pool of addresses for a limited