Portable Command
Single Area OSPF
This chapter provides information and commands concerning the following topics Configuring OSPF Mandatory commands Using wildcard masks with OSPF areas Configuring OSPF Optional commands Authentication Using MD5 encryption Propagating a default route Verifying OSPF configuration Configuration example Single area OSPF Configuring OSPF Mandatory Commands Starts OSPF process 123. The process ID is any positive integer value between 1 and 65,535. The process ID is not related to the OSPF area. The...
Setting Duplex Operation
fastethernet 0 1 Moves to interface configuration mode 2960Switch(config) interface fastethernet 0 1 Displays current MAC address forwarding table Deletes all entries from current MAC address forwarding table switch clear mac address-table dynamic Deletes only dynamic entries from table 2960Switch(config) mac address-table static aaaa.aaaa.aaaa vlan 1 interface fastethernet 0 1 Sets a permanent address to port fastethernet 0 1 in VLAN 1 2960Switch(config) no mac address-table static aaaa....
Sticky MAC Addresses
Sticky MAC addresses are a feature of port security. Sticky MAC addresses limit switch port access to a specific MAC address that can be dynamically learned, as opposed to a network administrator manually associating a MAC address with a specific switch port. These addresses are stored in the running configuration file. If this file is saved, the sticky MAC addresses do not have to be relearned when the switch is rebooted, and thus provide a high level of switch port security. Switch(config)...
Troubleshooting Spanning Tree
Displays all spanning-tree debugging events Displays spanning-tree debugging topology events Switch debug spanning-tree backbonefast Displays spanning-tree debugging BackboneFast events Switch debug spanning-tree uplinkfast Displays spanning-tree debugging UplinkFast event Switch debug spanning-tree switch state Displays spanning-tree port state changes
Security Device Manager Connecting with GUI
SDM has, by default, a one-time username and password set on a router. This one-time username password combination is cisco cisco. Plug your router's first Fast Ethernet (or Gigabit Ethernet) port into a switch. Plug your PC into the same switch. Configure your PC's IP address to be 10.10.10.2 29 (10.10.10.2 with a subnet mask of 255.255.255.248). Open your PC's Internet browser and enter the following command in the browser's address bar You will see a screen similar to the one shown in Figure...
The ping and traceroute Commands
This chapter provides information and commands concerning the following topics Examples of using the ping and the extended ping commands Disables ICMP redirects from this specific interface Reenables ICMP redirects from this specific interface Checks for Layer 3 connectivity with device at address w.x.y.z Enters extended ping mode, which provides more options The following table describes the possible ping output characters. The following table describes the possible ping output characters....
Troubleshooting
This chapter provides information and commands concerning the following topics Determining the gateway of last resort Determining the last routing update Interpreting the show interface command Clearing interface counters The show controllers command Operating system IP verification commands Displays a table about a specific protocol (for example, RIP or IGRP) Displays information about route w.x.y.z Displays a table of connected routes Determining the Gateway of Last Resort Router(config) ip...
Backing Up and Restoring Cisco IOS Software and Configurations
This chapter provides information and commands concerning the following topics Backing up configurations to a TFTP server Restoring configurations from a TFTP server Backing up the Cisco IOS Software to a TFTP server Restoring upgrading the Cisco IOS Software from a TFTP server Restoring the Cisco IOS Software from ROM Monitor mode using Xmodem Restoring the Cisco IOS Software using the ROM Monitor environmental variables and tftpdnld command Router(config) boot system flash imagename Loads the...
Configuring a Single Cisco Router
This chapter provides information and commands concerning the following topics Entering global configuration mode Configuring a router, specifically Configuring a serial interface Configuring a Fast Ethernet interface Creating a message-of-the-day (MOTD) 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 show commands to verify the router configurations EXEC commands in configuration mode the do command...
Password Recovery Procedures and the Configuration Register
This chapter provides information and commands concerning the following topics Console terminal baud rate settings Changing the console line speed CLI Changing the console line speed ROM Monitor mode Password-recovery procedures for Cisco routers Password-recovery procedures for 2960 series switches The last line of output tells you what the configuration register is set to. router(config) config- register 0x2142 Changes the configuration register to 2142. The configuration register is a 16-bit...
Using VLAN Database Mode
CAUTION The VLAN database mode has been deprecated and will be removed in some future Cisco IOS Software release. It is recommended to use only VLAN configuration mode. Creates VLAN 4 and names it Sales. The length of the name can be from 1 to 32 characters. Creates VLAN 10 and gives it a name of VLAN0010 as a default. Applies changes to the VLAN database and increases the revision number by 1. Applies changes to the VLAN database, increases the revision number by 1, and exits VLAN database...
Erasing VLAN Configurations
Removes the entire VLAN database from flash. WARNING Make sure there is no space between the colon ( ) and the characters vlan.dat. You can potentially erase the entire contents of the flash with this command if the syntax is not correct. Make sure you read the output from the switch. If you need to cancel, press to escape back to privileged mode (Switch ) Delete filename vlan.dat Delete flashivlan.dat confirm Switch Switch(config) interface fastethernet 0 5 Moves to interface configuration...
Configuring PAT Many Private to One Public Address Translation
All private addresses use a single public IP address and numerous port numbers for translation. Step 2 Define a pool of usable public IP addresses on your router that will perform NAT (optional). Use this step if you have many private addresses to translate. A single public IP address can handle thousands of private addresses. Without using a pool of addresses, you can translate all private addresses into the IP address of the exit interface (the serial link to the ISP, for example)....
Configuring Static NAT One Private to One Permanent Public Address Translation
Step 1 Define a static route on the remote router stating where the public addresses should be routed. ISP(config) ip route 64.64.64.64 255.255.255.128 s0 0 Informs the ISP where to send packets with addresses destined for 64.64.64.64 255.255.255.128. Step 2 Create a static mapping on your router that will perform NAT. Corp(config) ip nat inside source static 172.16.10.5 64.64.64.65 Permanently translates the inside address of 172.16.10.5 to a public address of 64.64.64.65. Use the command for...
Configuration Example DHCP
Figure 24-1 illustrates the network topology for the configuration that follows, which shows how to configure DHCP services on a Cisco IOS router using the commands covered in this chapter. Figure 24-4 Network Topology for DHCP Configuration Figure 24-4 Network Topology for DHCP Configuration Edmonton(config) interface fastethernet 0 0 Moves to interface configuration mode Edmonton(config-if) description LAN Interface Sets the local description of the interface Edmonton(config-if) ip address...
Configuration Example Ether Channel
Figure 14-2 illustrates the network topology for the configuration that follows, which shows how to configure EtherChannel using commands covered in this chapter. Figure 14-5 Network Topology for EtherChannel Configuration Figure 14-5 Network Topology for EtherChannel Configuration Turns off DNS queries so that spelling mistakes do not slow you down Changes the switch to VTP server mode Configures the VTP domain name to testdomain Creates VLAN 10 and enters VLAN configuration mode Returns to...
Dynamic Trunking Protocol DTP
Switch (config) interface fastethernet 0 1 Moves to interface configuration mode. Switch(config-if) switchport mode dynamic desirable Makes the interface actively attempt to convert the link to a trunk link. NOTE With the switchport mode dynamic desirable command set, the interface becomes a trunk link if the neighboring interface is set to trunk, desirable, or auto. Makes the interface able to convert into a trunk link. NOTE With the switchport mode dynamic auto command set, the interface...
Binary ANDing
Binary ANDing is the process of performing multiplication to two binary numbers. In the decimal numbering system, ANDing is addition 2 and 3 equals 5. In decimal, there are an infinite number of answers when ANDing two numbers together. However, in the binary numbering system, the AND function yields only two possible outcomes, based on four different combinations. These outcomes, or answers, can be displayed in what is known as a truth table You use ANDing most often when comparing an IP...
Shortcuts in Binary ANDing
Remember when I said that this was supposed to save you time when working with IP addressing and subnetting Well, there are shortcuts when you AND two numbers together An octet of all 1s in the subnet mask will result in the answer being the same octet as in the IP address. An octet of all 0s in the subnet mask will result in the answer being all 0s in that octet. Question 4 To what network does 172.16.100.45 belong, if its subnet mask is 255.255.255.0 Step 1 Convert both the IP address and the...
Subnetting a Class C Network Using Binary
You have a Class C address of 192.168.100.0 24. You need nine subnets. What is the IP plan of network numbers, broadcast numbers, and valid host numbers What is the subnet mask needed for this plan You cannot use N bits, only H bits. Therefore, ignore 192.168.100. These numbers cannot change. Step 1 Determine how many H bits you need to borrow to create nine valid subnets. 2n- 2 > 9 N 4, so you need to borrow 4 H bits and turn them into N bits. N 4, so you need to borrow 4 H bits and turn...
Subnetting a Class B Network Using Binary
You have a Class B address of 172.16.0.0 16. You need nine subnets. What is the IP plan of network numbers, broadcast numbers, and valid host numbers What is the subnet mask needed for this plan You cannot use N bits, only H bits. Therefore, ignore 172.16. These numbers cannot change. Step 1 Determine how many H bits you need to borrow to create nine valid subnets. 2n- 2 > 9 N 4, so you need to borrow 4 H bits and turn them into N bits. HHHHHHHHHHHHHHHH (Remove the decimal point for now) Step...
Assigning IPv6 Addresses to Interfaces
Enables the forwarding of IPV6 unicast datagrams globally on the router. Router(config) interface fastethernet 0 0 Moves to interface configuration mode. Automatically configures an IPv6 link-local address on the interface and enables IPv6 processing on the interface. NOTE The link-local address that the ipv6 enable command configures can be used only to communicate with nodes on the same link. Router(config-if) ipv6 address 3000 1 64 Configures a global IPv6 address on the interface and...
Configuring PPP on a Serial Line Optional Commands Compression
Router(config-if) compress predictor Enables the predictor compression algorithm Enables the stac compression algorithm Configuring PPP on a Serial Line (Optional Commands) Link Quality Ensures the link has a quality of x percent. Otherwise, the link will shut down. NOTE In PPP, the Link Control Protocol allows for an optional link-quality determination phase. In this phase, the link is tested to determine whether the link quality is sufficient to bring up any Layer 3 protocols. If you use the...
Security Device Manager Connecting with CLI
NOTE Cisco recommends that you use the Cisco Router and Security Device Manager (SDM) to configure your router. However, Cisco also realizes that most implementations of a router with SDM will be to use the command-line interface (CLI) for initial configuration then, after the routers have been added to the network, all future configuration will take place using SDM. If you have a router that has the SDM files already installed on it, console into the router and power the router on. If there is...
Cisco Discovery Protocol CDP
This chapter provides information and commands concerning the following topic Cisco Discovery Protocol (CDP) Displays global CDP information (such as timers) Displays information about neighbors Displays more detail about the neighbor device Displays information about the device named word Displays information about all devices Displays information about interfaces that have CDP running Displays information about specific interface x running CDP Displays traffic information packets in out...
Creating Standard ACLs
Router(config) access-list 10 permit 172.16.0.0 0.0.255.255 Read this line to say, All packets with a source IP address of 172.16.x.x will be permitted to continue through the internetwork. Arbitrary number between 1 and 99, or 1300 and 1999, designating this as a standard IP ACL. Packets that match this statement will be allowed to continue. Source IP address to be compared to. Router(config) access-list 10 deny host 172.17.0.1 Read this line to say, All packets with a source IP address of...
Static Routes in IPv6
NOTE Although not part of the CCNA exam objectives, the concept of static routes in IPv6 is one that network administrators dealing with IPv6 need to be comfortable with. NOTE To create a static route in IPv6, you use the same format as creating a static route in IPv4. Figure 25-3 illustrates the network topology for the configuration that follows, which shows how to configure static routes with IPv6. Note that only the static routes on the Austin router are displayed. Figure 25-3 Network...
SNMP and Syslog
This chapter provides information and commands concerning the following topics Router(config) snmp-server community academy ro Sets a read-only (ro) community string called academy Router(config) snmp-server community academy rw Sets a read-write (rw) community string called Router(config) snmp-server location 2nd Floor IDF Defines an SNMP string that describes the physical location of the SNMP server Router(config) snmp-server contact Scott Empson 555-5236 Defines an SNMP string that describes...
Configuration Example Single Area OSPF
Figure 10-1 illustrates the network topology for the configuration that follows, which shows how to configure Single Area OSPF using commands covered in this chapter. Figure 10-9 Network Topology for Single Area OSPF Configuration Network Network Figure 10-9 Network Topology for Single Area OSPF Configuration Network Network Austin(config) interface fastethernet 0 0 Moves to interface configuration mode. Austin(config-if) ip address 172.16.10.1 255.255.255.0 Austin(config-if) interface serial 0...
Extended System ID
Switch(config) spanning-tree extend system-id Enables extended system ID, also known as MAC address reduction. NOTE Catalyst switches running software earlier than Cisco IOS Software Release 12.1(8) EA1 do not support the extended system ID. Verifies extended system ID is enabled. Verifies extended system ID is enabled.
Configuring a Secondary Root Switch
Switch(config) spanning-tree vlan 5 root secondary Switch recalculates timers along with priority to allow the switch to become the root switch for VLAN 5 should the primary root switch fail. NOTE If all other switches have extended system ID support, this switch resets its priority to 28672. Therefore, if the root switch fails, and all other switches are set to the default priority of 32768, this becomes the new root switch. For switches without extended system ID support, the switch priority...
Configuring Frame Relay
Setting the Frame Relay Encapsulation Type Router(config) interface serial 0 0 0 Router(config-if) encapsulation frame-relay Turns on Frame Relay encapsulation with the default encapsulation type of cisco. Router(config-if) encapsulation frame-relay ietf Turns on Frame Relay encapsulation with the encapsulation type of ietf (RFC 1490). Use the ietf encapsulation method if connecting to a non-Cisco router. Setting the Frame Relay Encapsulation LMI Type Router(config-if) frame- relay lmi-type...
The Enhanced Bob Maneuver for Subnetting or How to Subnet Anything in Under a Minute
Legend has it that once upon a time a networking instructor named Bob taught a class of students a method of subnetting any address using a special chart. This was known as the Bob Maneuver. These students, being the smart type that networking students usually are, added a row to the top of the chart, and the Enhanced Bob Maneuver was born. The chart and instructions on how to use it follow. With practice, you should be able to subnet any address and come up with an IP plan in under a minute....
IP Subnet Zero
When you work with classical subnetting, you always have to eliminate the subnets that contain either all zeros or all ones in the subnet portion. Hence, you always used the formula 2N - 2 to define the number of valid subnets created. However, Cisco devices can use those subnets, as long as the command ip subnet-zero is in the configuration. This command is on by default in Cisco IOS Software Release 12.0 and later if it was turned off for some reason, however, you can re-enable it by using...
Hj wirelessN
This Setup Wizard will help you install the Wireless-N Broadband Router. Norton Internet Security User Guide Exit 200S Cisco Systems. Inc. All Rights Reserved Figure 15-3 shows the wizard asking you to unplug the power from your modem. When you have finished, click Next. Figure 15-8 Unplugging Power to the Modem Figure 15-8 Unplugging Power to the Modem Figure 15-4 shows the wizard asking you to unplug the modem from your computer. When you have finished, click...
VLSM Example
You follow the same steps in performing VLSM as you did when performing classical subnetting. Consider Figure 2-1 as you work through an example. Figure 2-1 Sample Network Needing a VLSM Address Plan A Class C network 192.168.100.0 24 is assigned. You need to create an IP plan for this network using VLSM. Once again, you cannot use the N bits 192.168.100. You can use only the H bits. Therefore, ignore the N bits, because they cannot change The steps to create an IP plan using VLSM for the...
Wireless Access Point Configuration Linksys 300N Access Point
NOTE The wireless access point (AP) used in this chapter is the Linksys Wireless-N Broadband Router. If you are using a different AP, the screen captures shown here may differ. It is important to use the most up-to-date firmware or drivers. This is especially true for the 300N AP because the 802.11n technology is still in draft stage. Therefore, check the AP manufacturer website for available updates. In the case of Linksys, its website for updates is http www.linksys.com download. Figure 15-1...