Vro configuration in basic network learning

The software configuration of a router is much more complicated than that of its hardware. What is different from that of other network access devices is that it is not only complicated in the hardware structure, it also integrates a wealth of software systems. A vro has its own independent and powerful software operating system, and its functions are quite complex and powerful, because it has to face various network protocols around the world, just like a person who can speak various languages. However, the operating systems of different brands are different, and their configuration methods are also different. However, Cisco is always a template of other brands in terms of routers, most other brands are imitated to a certain extent, so we will introduce the basic operations of the IOS operating system of the Cisco router in this section.

1. Router Startup Process

The router must be configured properly to implement its routing function. However, to understand the principle of the router's IOS function, let's take a look at the router startup process, just like starting a computer.

When the router is started, execute the program in the ROM, perform self-check, and then check a memory unit called config-register to determine whether to go to the ROM Monitoring Program, to the IOS subset, or to guide IOS. Then, check whether there is a configuration file in NVRAM, load IOS, and decompress IOS (many # are displayed at this time #). If you press the + key combination, the process of loading and guiding IOS is terminated and enters the ROM monitoring program status. Otherwise, after the IOS boot, the control is handed over to IOS. IOS reads config-register and determines whether to ignore the existing configuration file (0x2142) or use the existing configuration file (0x2102 ). Next, set the interfaces according to the preparation file to create a work environment. Finally, a prompt is displayed, waiting for the user to type the command. At the prompt "Host Name>", you can directly type the command.

If there is no configuration file for a brand-new machine, the router will enter an automatic conversational configuration state, and many questions will be raised to the user, and the matching configuration will be completed. Of course, you can also skip it and use commands to configure it. You can also enter the conversational configuration status again by typing setup at the prompt.

Ii. vro configuration methods

Because the router does not have its own input device, When configuring the router, it is generally configured to connect to various interfaces of the router through another computer. Because the network conditions connected by the vro may be ever-changing, a flexible configuration method must be provided for the vro to facilitate the management of the vro. Generally, you can configure a vro in the following ways:

1. Console mode

This method is generally used to initialize the vro. It connects the serial port of the PC directly to the vro Console port "Console" through a dedicated configuration line, run terminal simulation software on a PC Computer (such as a super-terminal in a Windows system) to communicate with the vro and complete the configuration of the vro. On the physical connection, you can also directly connect the serial port of the PC to the Auxiliary Port AUX of the router through a dedicated configuration line to configure the router.

2. Remote Logon (Telnet)

This is configured through the TELNET program that comes with the operating system (for example, Windows \ Unix \ Linux and other systems all have such a remote access program ). If a vro already has some basic configurations and requires at least one valid common port, you can establish communication with the vrotelnet by running the remote login (Telnet) program computer as the virtual terminal of the vro, complete the router configuration.

3. network management workstation Mode

In addition to the preceding two methods, a vro also provides a network management workstation configuration method, which is implemented through an SNMP network management workstation. In this way, you can configure a router by running the network management software provided by the router manufacturer, such as Cisco CiscoWorks, or some third-party network management software, such as HP OpenView, this method is generally used when the vro is already on the network, but you want to modify the vro configuration.

4. TFTP Server Mode

This is configured through the TFTP server in the network server. TFTP (Trivial File Transfer Protocol) is a simple TCP/IP File Transfer Protocol, the configuration file can be transferred from the vro to the TFTP server, or from the TFTP server to the vro. TFTP does not require a user name or password. It is very easy to use.

The preceding describes how to configure a vro. However, it must be noted that the first configuration of a vro must be performed by connecting to the control port (Console) of the vro, in this case, the hardware of the terminal is set to: baud rate: 9600, data bit: 8, stop bit: 1, and parity: none.

Iii. vro configuration user mode

There are two main ways to configure a vro: one is manual configuration, which is to configure the vro through command line after entering the ios of the vroios; the other is to run the "Setup.exe" program in the configuration software included in the vro. This is an interactive configuration software provided by IOS and is suitable for new users who are not familiar with IOS commands.

After carefully studying the configuration commands of IOS, You can manually configure the vro to greatly improve the efficiency. IOS has multiple levels of operations. Different commands are used at different levels, and the configuration work is different. When distinguishing between different levels, we mainly look at what is the prompt symbol of the router IOS. Different operation levels should have different prompts.

Level 1: User Mode

When you enter the vrotelnet through a terminal or Telnet, the system prompts the user to enter the password. After the password is entered, the vrotelnet level is 1st, that is, the user mode level. At this time, the system prompt is "> ". If the vro name is cisco3640, the prompt is "cisco3640> ". At this level, you can only view the basic status of the vro and cannot set the status.

Level 1: privileged Mode

In user mode, enter "enable" first, and then the corresponding password to enter the 2nd-level privileged mode. The system prompt in privileged mode is "#". If the vro is cisco3640, the prompt is as follows:

Cisco3640> enable
Password ://////////////
Cisco3640 #

At this level, you can use the show and debug commands for configuration check. You cannot modify the vro configuration. to modify the vro configuration, you must enter the vro level 3rd.

Level 3rd: Configuration Mode

In this mode, you can modify the vro configurations. Enter the "config terminal" command in privileged mode, and the prompt is "(config )#". As follows:

Cisco3640 # config terminal
Cisco3640 (config )#

In this case, you can modify the configurations of A vro, such as configuring the static route table of the vro. For detailed configuration commands, see the vro configuration document. If you want to configure a specific port, you also need to enter the level 4th.

Level 4th: Port Configuration Mode

Vrouters have various ports, such as 10/100 Mbps Ethernet ports and synchronization ports. To configure these ports, you must enter the port configuration mode. For example, if you want to configure Ethernet port 0 (the ports on the vro are numbered, please refer to the random document on the vro), run the "interface ethernet0" command as follows:

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Cisco3640 (config) # interface ethernet0
Cisco3640 (config-int )#

As we have mentioned above, we mainly identify the current vro user mode through the router IOS prompt. In order to facilitate your understanding, we will introduce several basic command prompts of the vro to you.

(1) router>

The vro is in the USER command status. You can view the connection status of the vro and access other networks and hosts, but cannot view and change the vro settings.

(2) router #

Enter enable at the router> prompt, and the vrouter enters the privileged command status router #. In this case, you can not only execute all user commands, but also view and change the vro settings. If you type exit in privileged mode, return to user mode. You cannot configure the vro in privileged mode. You must enter the config terminal command to enter the global configuration mode.

(3) router (config )#

Enter configure terminal at the router # prompt, and the prompt router (config) # appears. At this time, the vro is in the global setting state, and you can set the global parameters of the vrouter.

(4) router (config-if) #, router (config-line) #, and router (config-router )#......

The vro is in the local setting state. You can set a local parameter of the vro. There are many interfaces on the vro, such as multiple serial ports and multiple Ethernet ports. Many parameters need to be configured for each interface. These configurations cannot be solved by one command, therefore, you must enter the local configuration mode of an interface or component. Once you enter the local configuration mode of an interface or part, the command you type is only valid for this interface, and only the commands that can be received by this interface can be entered. For example, to enter serial interface 1 (S1), you need to configure the following content: first, synchronous or asynchronous; second, baud rate; third, DCE or DTE fourth, what is the IP address; fifth, disable or enable it. Sixth, what protocol is used. The local mode has many kinds of prompts, similar to "Router (config-if )#".

(5) Enter ">" prompt status

The vro is in the RXBOOT status. Press ctrl-break within 60 seconds after the vro is started to enter this status. In this case, the vro cannot complete normal functions. You can only perform software upgrade and manual boot.

(6) set the dialog status

This status automatically enters when a new vro is started. You can use the "Setup.exe" command in the privileged command status to enter this status. In this case, you can set the vro through dialog.

4. Common vro commands

The operating system of a router is a very powerful system. Especially in some high-end routers, it has a wealth of operating commands, just like our dossystem. Correct understanding of these commands is the most critical step for configuring a vro. Otherwise, you will not be able to talk about it at all, because generally, the vro is configured using commands. Next I will take the Cisco router as an example to talk about the common operation commands of the router. There are many IOS operation commands on the vro, which are described in the following categories.

1. Help commands

In IOS operations, you can enter "? "Get help from the system, so say "? "Is the help command of the router.

2. commands for changing the setting status

Because the vro has many different permissions and options, you must have corresponding commands to enter the corresponding setting status.

5. simple instance Configuration

Now, we use a specific example to describe the configuration process of the router. Currently, many organizations connect to the Internet through ddnleased lines. In this case, the ddnleased line connects to the synchronization port of the router through an NTU device, and then connects to the Ethernet port of the router through a twisted pair wire, the other end is connected to the Intranet network switch or Hub. Generally, you only need to purchase a vro with a synchronous port and an Ethernet port. Now we assume this vro is Cisco2611. We can simply configure a vro in this network environment as follows.

1. Define the name of the router Machine

If you want to define the vro machine name as cisco2611, enter the vroios IOS and run the following command:

Router> enable
Password :////////////
Router # config terminal
Router (config) # hostname cisco2611

2. Set the privileged mode password

As we can see from the device in the previous step, after entering "enable" for the vro operation, we need to enter the corresponding password. How can we set this password? To set the password, use the following command in the configuration mode (that is, the third-level user permission is required, not the user mode:

Router (config) # enable secret mypassword
To change the password to mypassword.

3. Configure Ethernet port information

In configuration mode, enter the following command:

Router (config) # interface ethernet 0/0
Router (config-if) # ip address 202.102.224.25 255.255.255.0

1st commands enter the port configuration mode, and 2nd commands configure the IP address and subnet mask of the port. It should be noted that at present, most of the routers produced by Cisco are based on modularization, and each module can have multiple ports. For example, if a network module with two ethernet interfaces is inserted in the router slot 0, the two ethernet ports are represented by "ethernet 0/0" and "ethernet 0/1, on the left side of the "/" symbol is the module slot number and on the right side is the port number.

4. Configure the synchronization Port

Router (config) # interface serial 0/0
Router (config-if) # ip address 202.102.211.108 255.255.255.255.248

The synchronization port of a ddnleased line generally connected to a router is represented by "serial 0/0", where "0/0" represents the Port location. Use the above 1st commands to enter the port configuration mode, and use the above 2nd commands to configure the IP address and subnet mask of the port.

5. Add a static route table

In this Internet access mode, a static route is used. Therefore, you must add a static route record with the following content:

Router (config) # ip router 0.0.0.0 0.0.0.0 202.102.211.107
This command forwards the packet sent to the router on the Intranet segment to the address 202.102.211.107 at the other end of the ddnline.

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6. view the configuration

Router # show running-config
Building configuration...
Current configuration:
!
Version 12.0:
Service config
Service timestamps debug uptime
Service timestamps log uptime
Service password-encryption
!
Hostname cisco2611
!
Enable secret 5 $1 $ MJrb $ o3NCu6DPwG/tgfbt71_v/
!
Ip subnet-zero
Ip domain-name pcworld.com.cn
Ip name-server 202.102.224.1
!
Interface Ethernet0/0
Ip address 202.102.224.25 255.255.255.0
!
Interface serial0/0
Ip address 202.102.211.108 255.255.255.248
!
Ip classless
Ip default-network 0.0.0.0
Ip router 0.0.0.0 0.0.0.0 202.102.211.107
No ip http server
!
Line con 0
Exec-timeout 1 0
Password 7 061C0731
Login
Transport input none
Line aux 0
Line vty 0 4
Access-class 2 in
Password 7 then f1f02
Login
!
End

The current configurations of the vro are listed above. You can run the show running-config command to view the configurations in NVRAM. To view the configurations in NVRAM, run the show startup-config command.

7. Save the Configuration

After modifying the vro configuration, you must store it in nvram for the next start to take effect. To do this, run the following command:

Router # copy running-config startup-config

After the above operations, the router configuration is basically complete. You can enter "? "Symbol to view which commands can be used currently. For statements not required in the configuration file, you only need to use the "no" command and then add the entire statement to delete the statements.

Now, the simple configuration method of the router is introduced. In the next article, we will introduce some specific application configurations in the advanced configuration of the router, to learn more about the advanced configurations of A vro, you must note that it is very useful!

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