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Setup Mode 47 exit Command exit Router#e Logs a user off Or exit Router>e Router(configexit if)#e Moves you back one level Router(config)# exit Router(config)#e Moves you back one level Router# disable Command disable Router#d Moves you from privileged mode back to user mode Router> logout Command logout Router#l Performs the same function as exit Setup Mode Setup mode start automatically if there is no startup configuration present. setup Router#s Enters startup mode from the command line NOTE: The answer inside the square brackets, [ ], is the default answer. If this is the answer you want, just press ®. Pressing Ç-C at any time will end the setup process, shut down all interfaces, and take you to user mode (Router>). NOTE: You cannot use setup mode to configure an entire router. It does only the basics. For example, you can only turn on either RIPv1 or Interior Gateway Routing Protocol (IGRP), but not Open Shortest Path First Protocol (OSPF) or Enhanced Interior Gateway Routing Protocol (EIGRP). You cannot create access control lists (ACL) here or enable Network Address Translation (NAT). You can assign an IP address to an interface, but not to a subinterface. All in all, setup mode is very limiting. 48 Keyboard Help Entering setup mode is not a recommended practice. Instead, you should use the command-line interface (CLI), which is more powerful: Would you like to enter the initial configuration dialog? [yes] : no Would you like to enable autoinstall? [yes] : no Autoinstall is a feature that tries to broadcast out all interfaces when attempting to find a configuration. If you answer yes, you must wait for a few minutes while it looks for a configuration to load. Very frustrating. Answer no. Keyboard Help The keystrokes in the following table are meant to help you edit the configuration. Because you’ll want to perform certain tasks again and again, Cisco IOS Software provides certain keystroke combinations to help make the process more efficient. ¬ Shows you where you made a mistake in entering a command config t Router#c ^ % Invalid input detected at ‘^’ marker. config t Router#c Router(config)# Ç-A Moves cursor to beginning of line ´-B Moves cursor back one word Ç-B (or ≤) Moves cursor back one character Ç-E Moves cursor to end of line Ç-F (or ≥≤) Moves cursor forward one character ´-F Moves cursor forward one word Ç-Z Moves you from any prompt back down to privileged mode $ Indicates that the line has been scrolled to the left terminal no editing Router#t Turns off the ability to use the previous keyboard shortcuts Router# terminal editing Router#t Router# Reenables enhanced editing mode (can use above keyboard shortcuts) show Commands 49 History Commands Ç-P (or ¯) Recalls commands in the history buffer in a backward sequence, beginning with the most recent command Ç-N (or ˘) Returns to more recent commands in the history buffer after recalling commands with the Ç-P key sequence terminal history size_ number Sets the number of commands in the buffer that can be recalled by the router (maximum 256) See the next row for an example terminal history size 25 Router#t Causes the router to now remember the last 25 commands in the buffer no terminal history size 25 Router#n Sets the history buffer back to 10 commands, which is the default NOTE: The history size command provides the same function as the terminal history size command. Be careful when you set the size to something larger than the default. By telling the router to keep the last 256 commands in a buffer, you are taking memory away from other parts of the router. What would you rather have: a router that remembers what you last typed in, or a router that routes as efficiently as possible? show Commands show version Router#s Displays information about the current Cisco IOS Software show flash Router#s Displays information about flash memory show history Router#s Lists all commands in the history buffer NOTE: The last line of output from the show version command tells you what the configuration register is set to. This page intentionally left blank PART III Configuring a Router Chapter 6 Configuring a Single Cisco Router This page intentionally left blank CHAPTER 6 Configuring a Single Cisco Router This chapter provides information and commands concerning the following topics: • Router modes • Entering global configuration mode • Configuring a router, specifically — Names — Passwords — Password encryption — Interface names — Moving between interfaces — Configuring a serial interface — Configuring a Fast Ethernet interface — Creating a message-of-the-day (MOTD) banner — Creating a login banner — Setting the clock time zone — Assigning a local host name to an IP address — The no ip domain-lookup command — The logging synchronous command — The exec-timeout command — Saving configurations — Erasing configurations • show commands to verify the router configurations • EXEC commands in configuration mode: the do command Router Modes Router> User mode Router# Privileged mode (also known as EXEC-level mode) Router(config)# Global configuration mode Router(config-if)# Interface mode 54 Configuring Passwords Router(config-subif)# Subinterface mode Router(config-line)# Line mode Router(config-router)# Router configuration mode TIP: There are other modes than these. Not all commands work in all modes. Be careful. If you type in a command that you know is correct—show running-config, for example—and you get an error, make sure that you are in the correct mode. Entering Global Configuration Mode Router> Limited viewing of configuration. You cannot make changes in this mode. Router# You can see the configuration and move to make changes. configure terminal Router#c Moves to global configuration mode. This prompt indicates that you can start making changes. Router(config)# Configuring a Router Name This command works on both routers and switches. hostname Cisco Router(config)#h The name can be any word you choose. Cisco(config)# Configuring Passwords These commands work on both routers and switches. enable password cisco Router(config)#e Sets enable password enable secret class Router(config)#e Sets enable secret password Password Encryption 55 line console 0 Router(config)#l Enters console line mode password console Router(config-line)#p Sets console line mode password to console login Router(config-line)#l Enables password checking at login line vty 0 4 Router(config)#l Enters vty line mode for all five vty lines password telnet Router(config-line)#p Sets vty password to telnet login Router(config-line)#l Enables password checking at login line aux 0 Router(config)#l Enters auxiliary line mode password backdoor Router(config-line)#p Sets auxiliary line mode password to backdoor login Router(config-line)#l Enables password checking at login CAUTION: The enable secret password is encrypted by default. The enable password is not. For this reason, recommended practice is that you never use the enable password command. Use only the enable secret password command in a router or switch configuration. You cannot set both enable secret password and enable password to the same password. Doing so defeats the use of encryption. Password Encryption service passwordRouter(config)#s encryption Applies a weak encryption to passwords enable password cisco Router(config)#e Sets enable password to cisco line console 0 Router(config)#l Moves to console line mode password Cisco Router(config-line)#p Continue setting passwords as above ... no service passwordRouter(config)#n encryption Turns off password encryption 56 Interface Names CAUTION: If you have turned on service password encryption, used it, and then turned it off, any passwords that you have encrypted will stay encrypted. New passwords will remain unencrypted. Interface Names One of the biggest problems that new administrators face is the interface names on the different models of routers. With all the different Cisco devices in production networks today, some administrators are becoming confused about the names of their interfaces. The following chart is a sample of some of the different interface names for various routers. This is by no means a complete list. Refer to the hardware guide of the specific router that you are working on to see the different combinations, or use the following command to see which interfaces are installed on your particular router: show ip interface brief router#s Router Model Port Location/Slot Number Slot/Port Type Slot Numbering Range Example 2501 On board Ethernet Interface-type number ethernet0 (e0) On board Serial Interface-type number serial0 (s0) & s1 On board Ethernet Interface-type number e0 & e1 On board Serial Interface-type number s0 & s1 On board Fast Ethernet Interface-type number fastethernet0 (fa0) Slot 0 WAC (WIN interface card) (serial) Interface-type number s0 & s1 On Board Fast Ethernet Interface-type 0/port fa0/0 Slot 0 WIC/VIC (voice interface card) Interface-type 0/port s0/0 & s0/1 v0/0 & v0/1 Slot 1 WIC/VIC Interface-type 1/port s1/0 & s1/1 v1/0 & v1/1 2514 1721 1760