Backup and Recovery Cisco Switches and Routers

Backup and Recovery
IT388-01 Routing & Switching I
November 17, 2008
Backup and Recovery
1. Describe the four-step process to locate and load the IOS. The four step process to locate and load the Internetwork Operating System, or IOS, is known as the boot sequence. These are the steps that a router must follow in order to bring the device into an operational status. The first step is known as POST. POST is a ROM based program that runs whenever the device is booted up. This is where the hardware will get checked to ensure they are “operational and present” (Lammle, pg 253). This will include each interface as well as any other hardware based device necessary to run the device. After the device passes POST, the IOS are loaded by another ROM based program called the bootstrap. The bootstrap will be responsible for finding and running the necessary files. All Cisco routers are set by default to load the IOS from flash memory (Lammle, pg 254). After the IOS is loaded, it will take over for the bootstrap in loading the next file or files. The IOS software will look for valid configuration files known as startup-config from NVRAM. The startup-config will only be stored in NVRAM if the administrator copies the running-config to that location (which he had better if he is smart). Finally, the startup-config, if present in NVRAM, will be loaded into RAM so it can be used to operate the router. This file is now called the running-config. If it is not present in NVRAM, a broadcast signal will be sent out any device interface that detects carrier detect for a TFTP host looking for configuration files (Lammle, pg 254). This detection would be used in VLANs.

2. What does a configuration register of 0x2101 specify? Provide an example of when you would see this configuration register value and the command to set the configuration register to 0x2101. The configuration register of 0x2101 is a command that changes the configuration register and tells the router to boot a small IOS from ROM. The configuration register is one way to alter how the router is booted. The command to change the configuration register looks like the following: Router(config)#config-register 0x2101 Router(config)#^Z One of the top reasons you would change the configuration register would be to force the system into ROM monitor mode, or ROMMON. This mode is used for recovering lost or forgotten passwords. Another reason you would use this configuration would be to enable booting from a TFTP.
3. What does a configuration register of 0x2142 specify? Provide an example of when you would see this configuration register value and the command to set the configuration register to 0x2142. The configuration register of 0x2142 is used to bypass startup-config and load the setup mode of the router. Certain situations warrant breaking into your router, like a forgotten password. The 0x2142 configuration will turn bit 6 on and allow you to change your password, after a series of commands of course (Lammle, pg 258). In order to change the configuration register, the commands would look like the following: Boot router Cntrl+break during boot up Router(boot)#config t Router(boot)(config)#config-register 0x2142 Router(boot)(config)#^Z Router(boot)#reload
4. Configure routers to use Telnet using the CCNA Virtual Labs simulator. Click on Net Visualizer Screen button. Here you will configure both routers so RouterB will Telnet into RouterA. a) Configure RouterA (double-click 2600 Router A to open the router) i) Change the router name to RouterA ii) Configure interface S0/0 so the IP address is 10.10.1.1/24 iii) Set the clock rate to 64000 iv) Configure the enable password to Hello v) Configure the Telnet password to Router1

b) Configure RouterB (double-click 2600 Router B to open the router) i) Change the router name to RouterB ii) Configure interface S0/1 so the IP address is 10.10.1.2/24 iii) At this point you should be able to Ping 10.10.1.1 iv) Telnet into RouterA, enter Telnet 10.10.1.1

c) Save your configuration. i) From the File menu, select Save. Name your simulator yourlastname.rsm. Be sure to submit the file to the dropbox.

5. Explain the different methods used by routers to perform name resolution. Give examples of the commands used to configure name resolution. There are two different methods used to resolve hostnames on routers. The first is building a host table on each router. This method will resolve hostnames only on devices that the table is built on. The hostname can be assigned up to eight different IP addresses (Lammle, pg 300). In order to configure a host table on a router, you would use the following commands. The command will use a format of ip host host_name tcp_port_number ip_address: • Router# config t • Router(config)#ip host 23 hostname1 192.168.10.1 • Router(config)#ip host 23 hostname1 192.168.25.10 • Router(config)#ip host 23 hostname2 192.168.25.10 • Router(config)#exit

As you can see, you can multiple hosts with different IP addresses just by adding more commands. You can then view your table by using the show command. The results would then be listed directly after the command. It would look like the following: • Router(config)#do show hosts The second option is to create a DNS server. The DNS server will eliminate you from having to create a hostname table on all of your devices (Lammle, pg 302). This comes in handy if you have a lot of devices to manage. Whenever you try to type a command into a Cisco device that it doesn’t understand, it will automatically try to resolve it through the DNS. Well this can be a little time consuming because you have to wait for the DNS name lookup to time out (Lammle, pg 302). By using a few commands you can get around the waiting period caused by name lookup by using the no ip domain-lookup command. Doing this will not allow the DNS to perform its job though. To enable DNS name resolution, you will use the following commands: ip domain-lookup, ip name-server, and ip domain-name. Here is how you would use them to setup the DNS: Router#config t Router(config)#ip domain-lookup Router(config)#ip name-server 10.10.3.0 Router(config)#ip domain-name domainname.com (that is my real website, please check it out. It needs to be updated though) Router(config)#^Z As shown above, the ip name-server will set the ip address for the DNS server. The domain name command will associate the address, domainname.com with the ip address. In order to test your work on the DNS server, you should be able to ping or telnet into your device using the hostname. 6. Using the CCNA Virtual Labs simulator, click on Net Visualizer Screen. Select Labs from View on the menu bar. Select Standard Labs and then Standard Lab 9. Complete the following labs: a. Using The Cisco Discovery Protocol b. Using Telnet After you have completed the lab, write a half page summary of about the Cisco Discovery Protocol (CDP), how to configure CDP and explain the benefits and risks of using CDP. Describe the use of Telnet.

Cisco Discovery Protocol is a protocol that helps administrators gather information about all devices connected to the network, whether local or remote. The information is best suited for documenting and troubleshooting your network. CDP is able to locate all the active interfaces by sending out packets at specified intervals. As with any tool there are some parameters that are configurable. In the case of CDP, the transmission time for how often packets are sent out can be configured. This is called the cdp timer. The time specified to transmit packets is in seconds. The second configurable parameter is the amount of time each device will hold on to a packet sent from a neighboring device. This is known as cdp holdtime. The hold time is also configured in seconds.The following is how these commands would be used to configure CDP. • 2600#sh cdp (gathers basic information about cdp) Global CDP information: Sending CDP packets every 60 seconds Sending a holdtime value of 180 seconds Sending CDPv2 advertisements is enabled • 2600#config t • 2600(config)#cdp timer 90 (if you wanted to increase the amount of time between transmissions) • 2600(config)#cdp holdtime 240 (increases holdtime to 240 seconds) • 2600(config)#^Z CDP is not always a good thing to leave running on your network. It has inherent security issues that could put your network at risk. Because CDP uses a form of broadcasting to manage the network, the amount of management overhead created by CDP may not be suitable for all networks (Bigelow, 2007). In an effort to combat some of the security concerns and overhead issues, CDP can be turned off. The command to turn off CDP would look like the following: • Router(config)#no cdp run • Router(config)#^Z

Telnet is very similar to CDP in that is lets you gather information about devices and run programs by creating a connection to remote devices. It is another tool for managing your network. In order to use Telnet, the device must have the telnet password wither set or set to no password. As a security feature, you have to set the enable or secret password on the remote device you are going to telnet into. This will stop any unwanted alterations to your network configurations. To enable telnet password, use the following commands. • 2600#config t • 2600(config)#line vty 0 4 • 2600(config)#password Router1 • 2600(config)#^Z

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References
Bigelow, J., (2007) Quick Tutorial on Evaluating CDP Products, TechTarget, Retrieved November 18, 2008 from http://searchdatabackup.techtarget.com/generic/0,295582,sid187_gci1300891,00.htm
Lammle, T., CCSI (2007) Managing a Cisco Internetwork, CCNA: Cisco Certified Network Associate Study Guide, Sixth Edition Exam 640-802, Chapter 5 (pp 251 – 312) Indianapolis, Indiana

References: Bigelow, J., (2007) Quick Tutorial on Evaluating CDP Products, TechTarget, Retrieved November 18, 2008 from http://searchdatabackup.techtarget.com/generic/0,295582,sid187_gci1300891,00.htm Lammle, T., CCSI (2007) Managing a Cisco Internetwork, CCNA: Cisco Certified Network Associate Study Guide, Sixth Edition Exam 640-802, Chapter 5 (pp 251 – 312) Indianapolis, Indiana