tailieunhanh - cisco 640 802 ccna portable command guide 2008 phần 5

Chú ý: Bạn không thể sử dụng chế độ thiết lập cấu hình toàn bộ một bộ định tuyến. Nó không chỉ là những điều cơ bản. Ví dụ, bạn chỉ có thể bật hoặc RIPv1 hoặc nội thất Gateway Routing Protocol (IGRP), nhưng không mở ngắn nhất Nghị định thư Path First (OSPF), Nội vụ tăng cường | Configuring a Default Route on a Router 71 Exterior Border Gateway Protocol eBGP 20 EIGRP internal 90 Open Shortest Path First Protocol OSPF 110 Intermediate System-to-Intermediate System Protocol IS-IS 115 RIP 120 Exterior Gateway Protocol EGP 140 On-Demand Routing 160 EIGRP external 170 Internal Border Gateway Protocol iBGP external 200 Unknown 255 By default a static route is always used rather than a routing protocol. By adding an AD number to your ip route statement however you can effectively create a backup route to your routing protocol. If your network is using EIGRP and you need a backup route add a static route with an AD greater than 90. EIGRP will be used because its AD is better lower than the static route. If EIGRP goes down however the static route will be used in its place. This is known as a floating static route. If a static route refers to an exit interface rather than a next-hop address the destination is considered to be directly connected and is therefore given an AD of 0 rather than 1. Configuring a Default Route on a Router Router config ip route Send all packets destined for networks not in my routing table to . Router config ip route serial 0 0 0 Send all packets destined for networks not in my routing table out my serial 0 0 interface. 72 Configuration Example Static Routes Verifying Static Routes To display the contents of the IP routing table enter the following command Router show ip route NOTE The codes to the left of the routes in the table tell you from where the router learned the routes. A static route is described by the letter s. Configuration Example Static Routes Figure 7-1 illustrates the network topology for the configuration that follows which shows how to configure static routes using the commands covered in this chapter. Figure 7-6 Network Topology for Static Route Configuration NOTE The host names passwords and interfaces have all been configured using the commands