Basic Router Configuration PDF

Welcome to Basic Router Configuration! Have you ever run a relay? The first person runs the first leg of the race and hands off the baton to the next runner, who continues forward in the second leg of the race and hands off the baton to the third runner, and on it goes. Routing packets is very simi...

Welcome to Basic Router Configuration! Have you ever run a relay? The first person runs the first leg of the race and hands off the baton to the next runner, who continues forward in the second leg of the race and hands off the baton to the third runner, and on it goes. Routing packets is very similar to a relay. But if the first runner does not know where to find the second runner, or drops the baton in the first leg, then that relay team will most certainly lose the race. Routing packets is very similar to a relay. As you know, routing tables are created and used by routers to forward packets from their local networks on to other networks. But a router cannot create a routing table or forward any packets until it has been configured. If you plan to become a network administrator you definitely must know how to do this. The good news? It is easy! This module has Syntax Checker activities so that you can practice your configuration commands and The task to configure a router interface is very similar to a management SVI on a switch. Specifically, it includes issuing the following commands: **Note:** When a router interface is enabled, information messages should be displayed confirming the enabled link. Although the **description** command is not required to enable an interface, it is good practice to use it. It can be helpful in troubleshooting on production networks by providing information about the type of network connected. For example, if the interface connects to an ISP or service carrier, the **description** command would be helpful to enter the third-party connection and contact information. **Note:** The *description-text* is limited to 240 characters. Using the **no shutdown** command activates the interface and is similar to powering on the interface. The interface must also be connected to another device, such as a switch or a router, for the physical layer to be active. **Note:** On inter-router connections where there is no Ethernet switch, both interconnecting interfaces must be configured and enabled. There are several commands that can be used to verify interface configuration. The most useful of these is the **show ip interface brief** and **show ipv6 interface brief** commands. Basic SHOW commands 1. show running-config: Displays the current configuration running on the device. 2. show startup-config: Shows the configuration stored in NVRAM that will be used on the next reboot. 3. show version: Provides details about the IOS version, system uptime, and hardware information. 4. show interfaces: Displays detailed information about all network interfaces, including status and statistics. 5. show ip interface brief: Summarizes the status of all interfaces, including IP addresses and operational status. 6. show vlan: Lists VLAN information and status. 7. show mac address-table: Displays the MAC address table, showing which MAC addresses are associated with which ports. If your local network has only one router, it will be the gateway router and all hosts and switches on your network must be configured with this information. If your local network has multiple routers, you must select one of them to be the default gateway router. This topic explains how to configure the default gateway on hosts and switches. For an end device to communicate over the network, it must be configured with the correct IP address information, including the default gateway address. The default gateway is only used when the host wants to send a packet to a device on another network. The default gateway address is generally the router interface address attached to the local network of the host. The IP address of the host device and the router interface address must be in the same network. For example, assume an IPv4 network topology consisting of a router interconnecting two separate LANs. G0/0/0 is connected to network 192.168.10.0, while G0/0/1 is connected to network 192.168.11.0. Each host device is configured with the appropriate default gateway address. Default Gateway on a Switch A switch that interconnects client computers is typically a Layer 2 device. As such, a Layer 2 switch does not require an IP address to function properly. However, an IP configuration can be configured on a switch to give an administrator remote access to the switch. To connect to and manage a switch over a local IP network, it must have a switch virtual interface (SVI) configured. The SVI is configured with an IPv4 address and subnet mask on the local LAN. The switch must also have a default gateway address configured to remotely manage the switch from another network. The default gateway address is typically configured on all devices that will communicate beyond their local network. To configure an IPv4 default gateway on a switch, use the **ip default-gateway** *ip-address* global configuration command. The *ip-address* that is configured is the IPv4 address of the local router interface connected to the switch. **Note:** Packets originating from host computers connected to the switch must already have the default gateway address configured on their host computer operating systems. A workgroup switch can also be configured with an IPv6 address on an SVI. However, the switch does not require the IPv6 address of the default gateway to be configured manually. The switch will automatically receive its default gateway from the ICMPv6 Router Advertisement message from the router. What did I learn in this module? **Configure Initial Router Settings** The following tasks should be completed when configuring initial settings on a router. 1. Configure the device name. 2. Secure privileged EXEC mode. 3. Secure user EXEC mode. 4. Secure remote Telnet / SSH access. 5. Secure all passwords in the config file. 6. Provide legal notification. 7. Save the configuration. **Configure Interfaces** For routers to be reachable, the router interfaces must be configured. The Cisco ISR 4321 router is equipped with two Gigabit Ethernet interfaces: GigabitEthernet 0/0/0 (G0/0/0) and GigabitEthernet 0/0/1 (G0/0/1). The tasks to configure a router interface are very similar to a management SVI on a switch. Using the **no shutdown** command activates the interface. The interface must also be connected to another device, such as a switch or a router, for the physical layer to be active. There are several commands that can be used to verify interface configuration including the **show ip interface brief** and **show ipv6 interface brief**, the **show ip route** and **show ipv6 route**, as well as **show interfaces**, **show ip interface** and **show ipv6 interface.** **Configure the Default Gateway** For an end device to communicate over the network, it must be configured with the correct IP address information, including the default gateway address. The default gateway address is generally the router interface address for the router that is attached to the local network of the host. The IP address of the host device and the router interface address must be in the same network. To connect to and manage a switch over a local IP network, it must have a switch virtual interface (SVI) configured. The SVI is configured with an IPv4 address and subnet mask on the local LAN. The switch must also have a default gateway address configured to remotely manage the switch from another network. To configure an IPv4 default gateway on a switch, use the **ip default-gateway ip-address** global configuration command. Use the IPv4 address of the local router interface that is connected to the switch.