CCNA Portable Command Guide
Terms
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- Class A address leading bit pattern/1st octet/notes
- 0xxxxxxx/0–127/ 0 is invalid, 127 reserved for loopback testing
- Class B address leading bit pattern/1st octet/notes
- 10xxxxxx/128–191/
- Class C address leading bit pattern/1st octet/notes
- 110xxxxx/192–223/
- Class D address leading bit pattern/1st octet/notes
- 1110xxxx/224–239/Reserved for multicasting
- Class E address leading bit pattern/1st octet/notes
- 1111xxxx/240–255/Reserved for future use or testing.
- Use subnets with all zeroes or ones.
- Router(config)# ip subnet-zero
- Requirements for route summarization.
- 1) Routers need to be running a classless routing protocol, as they carry subnet mask information with them in routing updates. (Examples are RIP v2, OSPF, EIGRP, IS-IS, and BGP.) 2) Addresses need to be assigned in a hierarchical fashion for the summarized address to have the same high-order bits
- If Ethernet LAN port or connection what's the port type, what's it connected to, what's the cable?
- RJ-45. Ethernet hub or Ethernet switch. RJ-45.
- If T1/E1 WAN port or connection what's the port type, what's it connected to, what's the cable?
- RJ-48C/CA81A T1 or E1 network Rollover
- If Console what's the port type, what's it connected to, what's the cable?
- 8 pin Computer COM port Rollover
- If Aux what's the port type, what's it connected to, what's the cable?
- 8 pin Modem RJ-45
- If BRI S/T what's the port type, what's it connected to, what's the cable?
- RJ-48C/CA81A NT1 device or PINX RJ-45
- If BRI U WAN what's the port type, what's it connected to, what's the cable?
- RJ-49C/CA11A ISDN network RJ-45
- To cable computer COM port to console of router/switch
- Use rollover cable
- To cable computer NIC to switch/hub
- Use straight-through cable
- To cable computer NIC to computer NIC
- Use crossover cable
- To cable switch or hub port to router's Ethernet port
- Use straight-through cable.
- To cable switch or hub port to switch or hub port
- Use crossover cable (check for uplink button or toggle switch to defeat this)
- To cable router's Ethernet port to router's Ethernet port
- Use crossover cable
- To cable computer NIC to router's Ethernet port
- Use crossover cable
- To cable router's serial port to router's serial port
- Use Cisco serial DCE/DTE cables
- List all commands available in the current command mode
- Router#?
- List all the possible command choices that start with c
- Router#c?
- What tells you that there are more parameters that need to be entered
- % Incomplete Command
- Show all subcommands for a command.
- Router#command ?
- No error message or 'Incomplete Command' message means the command was entered -
- successfully Router#
- Move user from user mode to privileged mode in router or switch
- Router>enable Router# or switch>enable switch#
- Log a user off from privileged (router) or user mode (router and switch)
- Router#exit or Router>exit or switch>exit
- To move back one level
- Router(config-if)#exit Router (config)# or Router(config)#exit Router#
- To move from privileged mode back to user mode in router or switch
- Router#disable Router> or switch#disable
- Alternative to 'exit' command
- Router#logout
- To enter startup mode from the command line if no startup config present.
- Router#setup
- Move cursor to beginning of line
- Ctrl A
- Move cursor back one word
- Esc b
- Move cursor back one character
- Ctrl b (or <- )
- Move cursor to end of line
- Ctrl e
- Move cursor forward one character
- Ctrl f (or -> )
- Move cursor forward one word
- Esc f
- Move from any prompt back down to privileged mode
- Ctrl z
- What indicates that the line has been scrolled to the left
- $
- Turn off the ability to use keyboard shortcuts
- Router#terminal no editing
- Re-enable enhanced editing mode to use keyboard shortcuts
- Router#terminal editing
- Recall commands in the history buffer in a backward sequence, beginning with the most recent command
- Ctrl p (or up arrow)
- Return to more recent commands in the history buffer after recalling commands with ctrl p key sequence
- Ctrl n (or down arrow)
- Set the number of commands in the buffer that can recalled by the router (maximum number is 256)
- Router#terminal history size number or Router#history size number
- Display information about currently loaded IOS including configuration register (router) or software and hardware (switch)
- Router# show version or switch# show version
- Display information about flash memory
- Router#show flash
- List all commands used at this edit level in the history buffer.
- Router#show history
- Indication of user mode
- Router> Limited viewing of config cannot make changes in this mode.
- Indicator of privileged mode
- Router# Can see config and move to make changes
- Indicator of global configuration mode
- Router(config)#
- Indicator of interface mode
- Router(config-if)#
- Indicator of subinterface mode
- Router(config-subif)#
- Indicator of line mode
- Router(config-line)#
- Indicator of router configuration mode
- Router(config-router)#
- Move to global config mode.
- Router#config terminal
- Configure a router or switch name. Includes 1900 series switches.
- Router(config)# hostname shem or (config)#hostname shem
- Set enable password on router or switch (2900/2950).
- Router(config)# enable password shem or 2900Switch(config)# enable password shem
- Set enable secret password on router or switch
- Router(config)# enable secret shem
- Enter console-line mode on router or switch (2900/2950)
- Router(config)#line con 0 or 2900Switch(config)# line con 0
- Set console-line mode password to shem on switch or router (2900/2950)
- Router(config-line)# password shem or 2900Switch(config-line)# password shem
- Enable password checking at login for router or switch (2900/2950)
- Router(config-line)# login or 2900Switch(config-line)# login
- Enter vty line mode for all five vty lines on router or switch
- Router(config)# line vty 0 4
- Set vty password to shem
- Router(config-line)# password shem
- Enter auxiliary line mode
- Router(config)# line aux 0
- Apply a weak encryption to passwords (from time of entry onwards)
- Router(config)# service password-encryption
- Display statistics for all interfaces (router) or interface configuration and status of line: up/up, up/down, admin down (switch)
- Router# show interfaces or switch# show interfaces
- Display statistics for a specific interface
- Router# show interface type number
- Display a summary of all interfaces, including status and IP address assigned
- Router# show ip interface brief
- Display statistics for interface hardware. Statistics display the clock rate if set and if the cable is DCE, DTE, or not attached
- Router# show controllers type number
- Display time set on device
- Router# show clock
- Display local host-to-IP address cache. These are the names and addresses of hosts on the network to which you can connect
- Router# show hosts
- Display all users connected to device
- Router# show users
- Display the ARP table
- Router# show arp
- Display status of configured Layer 3 protocols
- Router# show protocols
- Display configuration saved in NVRAM.
- Router# show startup-config or switch# show start
- Display configuration currently in RAM (router) or DRAM (switch)
- Router# show running-config [pre 12.0] more system:running-config [12.x] or switch# show running-config
- Move to interface Serial x/y mode
- Router(config)# int sx/y
- Define optional locally significant descriptor of the link (routers and switches).
- Router(config-if) #description Blah blah
- Assign address and subnet mask to serial interface
- Router(config-if)# ip address a.a.a.a m.m.m.m
- Assign a clock rate for the serial interface (DCE only)
- Router(config-if)# clock rate rrrrr
- Turn interface on
- Router(config-if)# no shut
- Move to FAst ethernet x/y interface mode
- Router(config)# int fax/y
- Create a MOTD banner.
- Router(config)# banner motd # Blah blah# Where the non-initial # is a delimiter
- Set the time zone for display purposes based on CUT.
- Router(config)# clock timezone thezone disp
- Assign a locally significant host name to an IP address.
- Router(config)# ip host shem a.a.a.a
- Turn off trying to automatically resolve an unrecognized command to a local host name if one is not going to set up DNS.
- Router(config)# no ip domain-lookup
- Turn on synchronous logging. Information items sent to console will not interrupt the command one types. The command will be moved to a new line
- Router(config-line)# logging synchronous (The informational line does not get inserted into the middle of the command one was trying to type. If one were to continue typing, the command would execute properly, even though it looks wrong on the screen.)
- Set time limit when console automatically logs off.
- Router(config-line)# exec-timeout m s (Don't use 0 0 in production as it means no timeout.)
- Save the running-config from DRAM to local NVRAM Router will execute commands in order they were entered on next reload
- Router# copy run start [pre 12.0] copy system:running-config nvram:startup-config [12.x] (Doesn't exist for 1900 series switch)
- Save the running-config remotely to TFTP server
- Router# copy run tftp [pre 12.0] copy system:running-config tftp: [12.x] Will have to reply IP address of TFTP server & dest file name.
- Delete the startup-config file from NVRAM without affecting dynamic memory.
- Router# erase start [pre 12.0] erase nvram: [12.x] (Reload the router to clear the running-config.)
- Default routing in static case using next-hop address
- Router(config)# ip route 0.0.0.0 0.0.0.0 a.a.a.a
- Default routing in static case specifying exit interface
- Router(config)#ip route 0.0.0.0 0.0.0.0 typeport
- Display contents of IP routing table
- Router# show ip route (The codes to the left of the routes in the table tell you from where the router learned the routes. A static route is described by the letter S.)
- Instruct IOS to forward packets destined for an unknown subnet to the best supernet route. A supernet route covers a range of subnets with a single entry. Cmd used in RIP.
- Router(config)# ip classless
- Enable RIP (v1 or v2) as a routing protocol from this mode.
- Router(config)# router rip
- Specify the network number of the directly connected network you want to advertise. In RIP-1, RIP-2, IGRP one needs to advertise only the classful network number.
- Router(config-router)# network w.x.y.z
- RIP updates will not be sent out an interface
- Router(config-router)# passive-interface typeport
- Define a specific neighbor with which to exchange information
- Router(config-router)# neighbor a.b.c.d
- Turn off split horizon (on by default)
- Router(config-router)# no ip split-horizon
- Change timers in RIP in seconds except where specified.
- Router(config-router# timers basic upd inv holddwn flush sleep(ms)
- Limit the number of paths for load balancing to x
- Router(config-router)# maximum-paths x (4 = default, 6 = maximum)
- Generate a default route into RIP.
- Router(config-router)# default-information originate
- RIP will now send and receive RIP-2 packets globally as v1 is default
- Router(config-router)# version 2
- Make interface send only RIP-1 packets
- Router(config-if)# ip rip send version 1
- Make interface send only RIP-2 packets
- Router(config-if)# ip rip send version 2
- Make interface send both RIP-1 and RIP-2 packets
- Router(config-if)# ip rip send version 1 2
- Make interface receive only RIP-1 packets
- Router(config-if)# ip rip receive version 1
- Make interface receive only RIP-2 packets
- Router(config-if)# ip rip receive version 2
- Make interface receive both RIP-1 and RIP-2 packets
- Router(config-if)# ip rip receive version 1 2
- Display all RIP activity in real time
- Router# debug ip rip
- Display contents of the RIP database
- Router# show ip rip database
- Change back to RIP-1
- Router(config-router)# no version 2
- Change RIP routing to RIP-1 from router-config mode.
- Router(config-router)# version 1
- Turn off RIP-2's summarization of networks at the classful boundary.
- Router(config-router)# no auto-summary
- Re-enable RIP-2's summarization of networks at the classful boundary.
- Router(config-router)# auto-summary
- Enable IGRP routing process. No longer supported by Cisco as of Cisco IOS Software Release 12.3. If one uses Cisco IOS 12.3 or newer code, one must use either Enhanced IGRP (EIGRP) or one of the other standards—RIP-1, RIP-2, or OSPF.
- Router(config)# router igrp as-number (AS-number used in the IGRP routing process must match all other routers that are going to share routing updates in order for communication to take place.)
- Disable the IGRP routing process
- Router(config)# no router igrp as-number
- Remove network w.x.y.z from the IGRP routing process.
- Router(config-router)# no network w.x.y.z
- Set the bandwidth of this interface to x kilobits to allow IGRP to make a better routing decision
- Router(config-if)# bandwidth x
- Allow IGRP to accept unequal-cost routes
- Router(config-router)# variance x
- Show all IGRP events in real time.
- Router# debug ip igrp events
- Show IGRP updates between routers
- Router# debug ip igrp transactions
- Turn on the EIGRP process All routers in the same AS must use the same AS number
- Router(config)# router eigrp as-number (1 - 65535)
- Specify which network to advertise in EIGRP
- Router(config-router)# network w.x.y.z
- Log any changes to an EIGRP neighbor adjacency. Recommended for debugging.
- Router(config-router)# eigrp log-neighbor-changes
- Turn off the auto-summarization feature in EIGRP. Networks are summarized at the classful boundary by default in EIGRP.
- Router(config-router)# no auto-summary
- Enable manual summarization on this specific EIGRP interface for the given address and mask. Recommended practice is that one turns off automatic summarization, use the ip summary-address command, and summarize manually what one needs to.
- Router(config-if)# ip summary-address eigrp as-number w.x.y.z m.m.m.m
- Display an EIGRP neighbor table
- Router# show ip eigrp neighbors
- Display a detailed EIGRP neighbor table
- Router# show ip eigrp neighbors detail
- Display EIGRP information for each interface
- Router# show ip eigrp interfaces
- Display EIGRP information for a specific interface
- Router# show ip eigrp int type port
- Display EIGRP information for interfaces running a specific process
- Router# show ip eigrp int processnumb
- Display the EIGRP topology table which will display where feasible successors are.
- Router# show ip eigrp topology
- Display the number and type of packets sent and received in EIGRP.
- Router# show ip eigrp traffic
- Display events/actions related to the DUAL FSM in EIGRP.
- Router# debug eigrp fsm
- Display events/actions related to EIGRP packets
- Router# debug eigrp packet
- Display events/actions related to EIGRP neighbors
- Router# debug eigrp neighbor
- Advertise OSPF interface using the wildcard mask to determine which interfaces to advertise as being in which area.
- Router(config-router)# network w.x.y.z m.m.m.m area n
- Turn on specified OSPF process number. The process ID is any value between 1–65535. The process ID is not related to the OSPF area. Unlike IGRP or EIGRP, matching this number across all routers does not ensure network adjacencies will form.
- Router(config)# router ospf nnnn Router(config-router)#
- A 0 (zero) in a wildcard mask means
- Check the corresponding bit in the address for an exact match.
- A 1 (one) in a wildcard mask means
- Ignore the corresponding bit in the address. It can be either 1 or 0.
- Any OSPF interface with an exact address of 172.16.10.1 is to be put into area 0.
- Router(config-router)# network 172.16.10.1 0.0.0.0 area 0
- Any OSPF interface with an address of 172.16.x.x is to be put into area 0.
- Router(config-router)# network 172.16.10.0 0.0.255.255 area 0
- Any OSPF interface with any address is to be put into Area 0
- Router(config-router)# network 0.0.0.0 255.255.255.255 area 0
- Move to virtual interface Loopback 0. Loopback interfaces are always "up and up" and do not go down unless manually shut down. This makes Loopback interfaces great for using as an OSPF router ID.
- Router(config)# interface lo0
- Change OSPF interface priority to nn. A priority of 0 guarantees that the router never wins a designated router (DR) election, and 255 guarantees a tie in the election (tie broken by highest router ID).
- Router(config-if)# ip ospf priority nn
- Change the bandwidth in OSPF to recalculate the cost of the link.
- Router(config-if)# bandwidth nnn
- Change the OSPF cost metric to a value of nnnn. Cost = refbw/intbw
- Router(config-if)# ip ospf cost nnnn
- Turns on simple OSPF authentication. Password sent in clear text.
- Router(config-router)# area nn authentication
- Set OSPF key (password) to whatever
- Router(config-if)# ip ospf authentication-key whatever
- Enables OSPF authentication for specified area with MD5 password encryption
- Router(config-router)# area nn authentication message-digest
- Enable OSPF MD5 algorithm authentication for a particular key-id and key (password) which must be same as neighboring router.
- Router(config-if)# ip ospf message-digest-key key-id md5 key
- Change OSPF 'Hello' interval timer to n seconds. Must match for router to be neighbor.
- Router(config-if)# ip ospf hello-interval timer n
- Change OSPF 'dead' interval timer to nn seconds. Must match for routers to be neighbors.
- Router(config-if)# ip ospf dead-interval nn
- Create a default route in OSPF.
- Router(config)# ip route 0.0.0.0 0.0.0.0 int
- Set the default route to be propagated to all OSPF routers
- Router(config-router)# default-information-originate
- Display basic OSPF information
- Router# show ip ospf
- Display OSPF information as it relates to all interfaces
- Router# show ip ospf interface
- Display OSPF information for specified interface.
- Router#show ip ospf inttype intno
- List all OSPF neighbors and their states
- Router# show ip ospf neighbor
- Display a detailed list of OSPF neighbors
- Router# show ip ospf neighbor detail
- Display contents of OSPF database
- Router# show ip ospf database
- Clear entire routing table, forcing it to rebuild
- Router# clear ip route *
- Clear specific route to network a.b.c.d
- Router# clear ip route a.b.c.d
- Reset OSPF counters
- Router# clear ip ospf counters
- Reset entire OSPF process forcing OSPF to re-create neighbors, database, and routing table
- Router# clear ip ospf process
- Display all OSPF events
- Router# debug ip ospf events
- Display various OSPF states and DR and BDR election between adjacent routers
- Router# debug ip ospf adj
- Display OPSF packets
- Router# debug ip ospf packets
- Display information on flash memory (for the 2900/2950 series only)
- switch# show flash:
- Display current switch MAC address forwarding table
- switch# show mac-address-table
- Display information about switch Ethernet controller
- switch# show controllers ethernet-controller
- Display whether the switch passed POST
- switch# show post
- Display the current VLAN configuration
- switch# show vlan
- Display setting of virtual interface VLAN 1, the default VLAN on the switch
- switch# show interface vlan1
- Remove VLAN Trunking Protocol (VTP) information from 1900 series switch.
- 1900switch# delete vtp
- Reset 1900 series switch back to factory defaults
- 1900switch# delete nvram
- Restart a 1900 series switch
- 1900switch# reload
- Set the 1900 series user mode password to shem.
- 1900Switch(config)# enable password level 1 shem
- Set the 1900 series enable mode password to shem
- 1900Switch(config)# enable password level 15 shem
- Set the 1900/2900/2950 series enable secret password to shem.
- 1900Switch(config)# enable secret shem or 2900Switch(config)# enable secret shem
- Set 1900 series switch IP address and mask to allow for remote access
- 1900Switch(config)# ip address w.x.y.z m.m.m.m
- Set the 1900 series switch default gateway address to allow IP information an exit past the local network
- 1900Switch(config)# ip default-gateway w.x.y.x
- Force full-duplex operation on 1900/2900/2950 switches
- Switch(config-if)# duplex full
- Enable auto-duplex config on 1900/2900/2950 switches
- Switch(config-if)# duplex auto
- Force half-duplex operation on 1900/2900/2950
- Switch(config-if)# duplex half
- Force 10-Mbps operation on 2900/2950 switch
- 2900Switch(config-if)# speed 10
- Force 100-Mbps operation on 2900/2950 switches
- 2900Switch(config-if)# speed 100
- Enable auto-speed configuration on 2900/2950 switches
- 2900Switch(config-if)# speed auto
- Turn on HTTP service with 1900/2900/2950
- X900Switch(config)# ip http server
- Set port number for HTTP on 1900/2900/2950 switches. This port should be turned off for security reasons unless it is being used
- X900Switch(config)# ip http port 80
- Display current MAC address forwarding table on 1900/2900/2950 switches
- switch# show mac-address-table
- Delete all entries from current MAC address forwarding table 1900/2900/2950 switches
- switch# clear mac-address-table
- Delete only dynamic entries from MAC address table of 1900/2900/2950 switches
- switch# clear mac-address-table dynamic
- Set a permanent address of aaaa.aaaa.aaaa in the MAC address table for an interface in a 1900 switch
- 1900Switch(config)# mac-address-table permanent aaaa.aaaa.aaaa typeportnumb
- Delete all permanent entries in a 1900 switch MAC address table.
- 1900Switch# clear mac-address-table perm
- Make a 1900 switch interface secure
- 1900Switch(config-if)# port secure
- Allow only nn MAC addresses in the MAC table for this interface on a 1900 switch
- 1900Switch(config-if)# port secure max-mac-count nn
- Display the MAC address table with security information of a 1900 switch
- 1900Switch# show mac-address-table security
- Display the spanning-tree table of the switch (Cisco IOS 12.1 and later)
- Switch# show spanning-tree
- Display spanning-tree info for port type portno
- 2950# show spanning-tree int type portno
- Display spanning tree info for a specific VLAN
- 2950# show spanning-tree vlan x
- Display all informational messages about changes in the spanning tree topology
- 2950# debug spanning-tree {all}
- Change Spanning-Tree Priority of a Switch. In Cisco IOS 12.1 where nn can be from 1–65535. Lower number means better chance of being elected the root bridge. The default is 32768.
- Switch(config)#spanning-tree vlan 1 priority nn
- Change this switch to the root switch for VLAN x by lowering its priority to either 24576 or 100 less than current root bridge, whichever number is lower
- Switch# spanning-tree vlan x root
- Configure EtherChannel where x is the number of the channel-group and must match the other interface
- Switch(config-if)# channel-group x mode on
- Display detailed EtherChannel information
- Switch# show etherchannel x detail
- Display EtherChannel port information
- Switch# show etherchannel x port
- Display EtherChannel port-channel information
- Switch# show etherchannel x port-channel
- Display a one-line summary per channel-group in EtherChannel environment
- Switch# show etherchannel x summary
- Display 1900 series VLAN information
- 1900Switch# show vlan
- Display which ports belong to which VLAN on a 1900 switch
- 1900Switch# show vlan-membership
- Display information about VLAN n only on a 1900 switch
- 1900Switch# show vlan 2
- Create and name static VLAN nn on 1900 switch
- 1900Switch(config)# vlan n name shem
- Assign 1900 switch port to VLAN n
- 1900Switch(config-if)# vlan static n
- Assigning 2950 Switch Ports Using the range Command
- 2950Switch(config)# int range type crd/port/m - n Note space surrounding hyphen
- Set all 2950 ports to access mode
- 2950Switch(config-if-range)# switchport mode access
- Assign all 2950 ports to VLAN nn
- 2950Switch(config-if-range)# switchport access vlan 10
- Delete all VLAN information from the 1900 series switch and reset VTP parameters to the factory defaults
- 1900Switch# delete vtp
- Remove interface from 1900 series VLAN nn and puts it back into default VLAN 1
- 1900Switch(config-if)# no vlan static nn
- Remove only VLAN nn from 1900 series switch database
- 1900Switch(config)# no vlan nn name shem
- Display the complete VLAN database
- 2900Switch# show vlan
- Display a summary of the VLAN database
- 2900Switch# show vlan brief
- Display a summary of each switch interface, including speed and duplex settings
- 2900Switch# show interfaces
- Display information about VLAN packets a switch has received but is not capable of supporting
- 2900Switch# debug sw-vlan packets
- Turn trunking mode on in 1900 switch
- 1900Switch(config-if)# trunk on
- Turn port to trunking mode on 2900 series switch
- 2900Switch(config-if)# switchport mode trunk
- Set encapsulation type to Dot1Q on 2900 series switch. This is the default encapsulation type
- 2900Switch(config-if)# switchport trunk encapsulation dot1q
- Display trunking information about port 0/26 on 1900 series switch
- 1900Switch# show trunk A
- Change the 1900 series switch to VTP client mode
- 1900Switch(config)# vtp client
- Changes the 1900 series switch to default VTP server mode
- 1900Switch(config)# vtp server
- Change the 1900 series switch to VTP transparent mode
- 1900Switch(config)# vtp transparent
- Set the name of the 1900 series switch VTP management domain to shem
- 1900Switch(config)# vtp domain shem
- Set the VTP password to shem
- 1900Switch(config)# vtp password shem
- Display all 1900 series VTP information
- 1900Switch# show vtp
- Load IOS with image-name. If entered first it is the first place the router will go to look for the IOS.
- Router(config)# boot system flash image-name
- Load IOS with image-name from a TFTP server. Enter first if you want to go to a TFTP server first.
- Router(config)# boot system tftp image-name w.x.y.z
- Load IOS from ROM
- Router(config)# boot system rom
- Copies configuration file from TFTP server to DRAM
- Router# copy tftp run [pre 12.0] Router# copy tftp: system:running-config [12.x] Will have to supply IP address of TFTP server and file name to be retrieved.
- Backing Up IOS to TFTP Server
- Router# copy flash tftp 2900Switch# copy flash:filename tftp Will have to supply name of IOS image and address of TFTP server and dest file name.
- Restoring/Upgrading IOS from TFTP Server
- Router# copy tftp flash Will have to supply addr or name of remote host, source, dest filename. If Flash memory is full, must reply to erase it first.
- Firmware Upgrade of Catalyst 2950 Series Switch
- 2950Switch#archive tar /x tftp://w.x.y.x/filename.tar flash:
- Make switch now boot to this IOS
- 2950Switch(config)# boot system flash filename.bin
- Changes the router configuration register to nnnn
- router(config)# config-register 0xnnnn
- Password Recovery Procedures for Cisco Routers
- 1: Boot the router and interrupt the boot sequence as soon as text appears on the screen. 2: Change the configuration register to ignore contents of NVRAM (0x2142). 3: Reload the router. 4: Enter privileged mode. (Do not enter setup mode.) 5: Copy startup-config into running-config. 6: Change the password. router(config)# enable secret new 7: Reset configuration register back to default value (0x2102). 8: Save the configuration. 9: Verify configuration register. 10: Reload the router using reload command.
- Password Recovery for 2900/2950 Series Switches
- 1. Unplug the power supply from the back of the switch 2. Press and hold the Mode button on the front of the switch 3. Plug the switch back in 4. a) For the 2900 series switch Wait until the LED above port 1X goes out, then release the Mode button b. For the 2950 series switch Wait until the STAT LED goes out, then release the Mode button. 5. switch: flish_init 6. switch: load_helper 7. switch: flash: 8. switch: rename flash:config.text flash:config.old 9. switch: boot 10. Type n to exit the initial configuration dialog which takes you to user mode. 11. switch>en 12. switch#rename flash:config.old flash:config.text [to rename file back to original name]. 13. switch#copy flash:config.text system:running-config {Copies config file into memory} xx 2900Switch#config t (and change passwords as needed). xx. 2900Switch#copy run start
- Display global CDP information (such as timers)
- Router# show cdp
- Display information about neighbors
- Router# show cdp neighbors