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CCNA Guide to Cisco Networking. Chapter 8: Routing Protocols and Network Address Translation. Objectives. Understand the purpose and operation of network address translation (NAT) Configure static NAT, dynamic NAT, and dynamic NAT with overload
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CCNA Guide to Cisco Networking Chapter 8: Routing Protocols and Network Address Translation
Objectives • Understand the purpose and operation of network address translation (NAT) • Configure static NAT, dynamic NAT, and dynamic NAT with overload • Understand and configure port address translation (PAT) • Differentiate between nonroutable, routed, and routing protocols • Define Interior Gateway Protocols, Exterior Gateway Protocols, distance-vector routing protocols, and link-state routing protocols CCNA Guide to Cisco Networking
Objectives (continued) • Explain the concepts of count-to-infinity, split horizon, split horizon with poison reverse, and hold-down timers • Describe, configure, and monitor the interior routing protocols RIP and IGRP • Explain static routing and administrative distance • Configure static routing and default routes CCNA Guide to Cisco Networking
Network Address Translation • Static NAT • Dynamic NAT • Port Address Translation • Dynamic Nat with overload • Overlapping CCNA Guide to Cisco Networking
Network Address Translation (continued) CCNA Guide to Cisco Networking
Network Address Translation (continued) CCNA Guide to Cisco Networking
Network Address Translation (continued) CCNA Guide to Cisco Networking
Configuring Network Address Translation • Configure static NAT • Define static mapping between the inside address and the outside address • Define the router’s interfaces as inside or outside • Basic NAT interface assignment • RouterA(config)# int fa 0/0 • RouterA(config-if)# ip nat inside • RouterA(config-if)# int serial 0/1 • RouterA(config-if)# ip nat outside CCNA Guide to Cisco Networking
Configuring Dynamic NAT • Configure a standard access control list to define what internal traffic will be translated • Define a pool of addresses to be used for dynamic NAT allocation • Link the access list to the NAT pool • Define interfaces as either inside or outside CCNA Guide to Cisco Networking
Configuring Dynamic NAT (continued) • Dynamic NAT router configurations • RouterA(config)# access-list 1 permit 192.168.0.0 0.0.0.255 • RouterA(config)# ip nat pool PoolExample 209.86.192.200 209.86.192.240 netmask 255.255.255.0 • RouterA(config)# ip nat inside source list 1 pool PoolExample • RouterA(config)# int fa 0/0 • RouterA(config-if)# ip nat inside • RouterA(config-if)# int serial 0/1 • RouterA(config-if)# ip nat outside CCNA Guide to Cisco Networking
Configuring Port Address Translation To An Outside Interface • Configure PAT router commands • Configure a standard access list to define what internal traffic will be translated • Link the access list to the interface to be used for PAT • Define interfaces as either inside or outside CCNA Guide to Cisco Networking
Configuring Port Address Translation To An Outside Interface (continued) • PAT router commands • RouterA(config)# access-list 1 permit 192.168.0.0 0.0.0.255 • RouterA(config)# ip nat inside source list 1 interface serial 0/1 overload • RouterA(config)# interface serial 0/1 • RouterA(config-if)# ip nat outside • RouterA(config-if)# interface fa 0/0 • RouterA(config-if)# ip nat inside CCNA Guide to Cisco Networking
Configuring Port Address Translation To An Outside Interface(continued) CCNA Guide to Cisco Networking
Configuring Dynamic NAT With Overload • Dynamic NAT with overload is a mixture of dynamic NAT and PAT • Dynamic NAT: Pool of inside addresses to a small pool of outside addresses • PAT: Same pool of inside addresses to an single outside address • PAT function becomes available when pool of outside addresses are all in use • Use dynamic NAT and PAT configurations using the same pool of inside addresses CCNA Guide to Cisco Networking
Nonroutable Protocols • Peer-to-peer networks • Microsoft Windows operation systems • NetBIOS Enhanced User Interface (NetBEUI) • Very small • Fast • Efficient • Cannot scale CCNA Guide to Cisco Networking
Nonroutable Protocols (continued) CCNA Guide to Cisco Networking
Routed Protocols • Routed protocols • Support networks • Logical addresses • Transmission Control Protocol/Internet Protocol (TCP/IP) • Internetwork Packet Exchange/Sequence Packet Exchange (IPX/SPX) CCNA Guide to Cisco Networking
Routed Protocols (continued) CCNA Guide to Cisco Networking
Routing Protocols • Path determination • Routing tables • Metric • Autonomous system (AS) • Convergence • Interior gateway protocols (IGP) • Routing information protocol (RIP) • Interior gateway routing protocol (IGRP) • Enhanced Interior gateway routing protocol (EIGRP) • Open shortest path first (OSPF) • Exterior gateway protocols (EGP) • Border gateway protocol (BGP) CCNA Guide to Cisco Networking
Routing Protocols (continued) CCNA Guide to Cisco Networking
Routing Protocols (continued) CCNA Guide to Cisco Networking
Two Types Of IGPs • Distant vector and link-state • Distant-vector • Routing by rumor • Routing loops • Count-to-infinity • Split horizon • Split horizon with poison reverse • Hold-down timers CCNA Guide to Cisco Networking
Two Types Of IGPs (continued) • Link-state • Link-state advertisements (LSA) • Shortest path first (SPF) algorithm • Link-state packets • Common view of the topology • Floods or multicasts LSPs • Triggered updates CCNA Guide to Cisco Networking
Two Types Of IGPs (continued) CCNA Guide to Cisco Networking
Two Types Of IGPs (continued) CCNA Guide to Cisco Networking
Two Types Of IGPs (continued) CCNA Guide to Cisco Networking
Two Types Of IGPs (continued) CCNA Guide to Cisco Networking
Two Types Of IGPs (continued) CCNA Guide to Cisco Networking
Routing Information Protocol • RIP has the following attributes • Distance-vector routing protocol • Maximum hop count of 15 • 16 hops is considered infinity • Hop count is the only metric available for path selection • Broadcasts the entire routing table to neighbors every 30 seconds • Capable of load balancing • Easy to configure CCNA Guide to Cisco Networking
Enabling RIP Routing CCNA Guide to Cisco Networking
Enabling RIP Routing (continued) CCNA Guide to Cisco Networking
Configuring RIP Routing For Each Major Network • Design the network for the appropriate networks • Configure interfaces to be gateways for networks • Configure routing protocol • In router mode establish networks to be advertised CCNA Guide to Cisco Networking
Configuring RIP Routing For Each Major Network (continued) CCNA Guide to Cisco Networking
Configuring RIP Routing For Each Major Network (continued) CCNA Guide to Cisco Networking
“show ip protocol” and “debug ip rip” (continued) CCNA Guide to Cisco Networking
“show ip protocol” and “debug ip rip” (continued) CCNA Guide to Cisco Networking
“show ip route” Command CCNA Guide to Cisco Networking
“show ip route” Command (continued) CCNA Guide to Cisco Networking
“show ip route” Command (continued) CCNA Guide to Cisco Networking
Interior Gateway Routing Protocol • Proprietary distance-vector routing protocol • Supports hop count of 255 • 100 is the default hop count • Supports up to four equal cost paths • Routing table updates every 90 seconds CCNA Guide to Cisco Networking
Interior Gateway Routing Protocol (continued) • IGRP metrics • Hops: Number of routers between source and destination networks • Load: The load on a link in the path • Bandwidth: The speed of the link (default) • Reliability: Measures reliability with a scale of 0 to 255 • Delay: The delay on the medium (default) • MTU: The size of the datagram CCNA Guide to Cisco Networking
Interior Gateway Routing Protocol (continued) CCNA Guide to Cisco Networking
Interior Gateway Routing Protocol (continued) CCNA Guide to Cisco Networking
Interior Gateway Routing Protocol (continued) CCNA Guide to Cisco Networking
Interior Gateway Routing Protocol (continued) CCNA Guide to Cisco Networking
Static Routing • Adding static routes • Router(config)# ip route [destination network/destination ip address] [next hop ip address/forwarding interface] [administrative distance] • RouterD(config)# ip route 172.32.3.0 255.255.255.0 172.32.2.2 • Changing administrative distance • Default administrative distance of a static route is • 0 if a forwarding interface is configured • 1 if a next hop ip address is configured • Router(config)# ip route 192.168.5.0 255.255.255.0 192.168.4.2. 150 CCNA Guide to Cisco Networking
Static Routing (continued) CCNA Guide to Cisco Networking
Configuring A Default Route • Routing protocols do not behave equally with default routes • Router(config)# ip route 0.0.0.0 0.0.0.0 [next hop ip address/forwarding interface] [administrative distance] • Router(config)# ip default-network [forwarding ip address] CCNA Guide to Cisco Networking
Configuring A Default Route (continued) CCNA Guide to Cisco Networking
Summary • NAT is a technology that allows organizations to map valid external addresses to private or unregistered internal addresses • This allows organizations to maintain a separation between the Internet and the intranet (internal network) while still providing access to the Internet • Organizations can use NAT to allow many more people to access the Internet by sharing one or more valid public addresses • PAT allows an organization to map more than one internal private IP address to a public IP address CCNA Guide to Cisco Networking