[CCNA] Шпаргалка по командам Cisco

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[CCNA] Шпаргалка по командам Cisco
[CCNA] Шпаргалка по командам Cisco

Содержание

Системный администратор

[CCNA] Cisco Commands Cheat Sheet

Router Modes:

  • Router>: User mode = Limited to basic monitoring commands
  • Router#: Privileged mode (exec-level mode) = Provides access to all other router commands
  • Router(config)#: global configuration mode = Commands that affect the entire system
  • Router(config-if)#: interface mode = Commands that affect interfaces
  • Router(config-subif)#: subinterface mode = Commands that affect subinterfaces
  • Router(config-line)#: line mode = Commands that affect in lines modes (console, vty, aux…)
  • Router(config-router)#: router configuration mode

Changing switch hostname:

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Switch(config)# hostname SW1

Configuring passwords:

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SW1(config)# enable secret cisco    ! MD5 hash
SW1(config)# enable password notcisco    ! Clear text

Securing console port:

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SW1(config)# line con 0
SW1(config-line)# password cisco
SW1(config-line)# login

Securing terminal lines:

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SW1(config)# line vty 0 4
SW1(config-line)# password cisco
SW1(config-line)# login

Encrypting passwords:

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SW1(config)# service password-encryption

Configuring banners:

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SW1(config)# banner motd $
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
UNAUTHORIZED ACCESS IS PROHIBITED
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
$

Giving the switch an IP address:

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SW1(config)# interface vlan 1
SW1(config-if)# ip address 172.16.1.11 255.255.255.0    ! or DHCP
SW1(config-if)# no shutdown

Setting the default gateway:

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SW1(config)# ip default-gateway 172.16.1.1

Saving configuration:

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SW1# copy running-config startup-config
Destination filename [startup-config]?    ! Press enter to confirm file name.
Building configuration…
[OK]
! Short for write memory.
SW1# wr
Building configuration…
[OK]

Working environment:

name lookup, history, exec-timeout and logging behavior…, also valid for line con 0.

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SW1(config)# no ip domain-lookup
SW1(config)# line vty 0 4
SW1(config-line)# history size 15
SW1(config-line)# exec-timeout 10 30
SW1(config-line)# logging synchronous

Configuring switch to use SSH:

  • Configure DNS domain name:
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SW1(config)# ip domain-name example.com
  • Configure a username and password:
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SW1(config)# username admin password cisco
  • Generate encryption keys:

The size of the key modulus in the range of 360 to 2048

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SW1(config)# crypto key generate rsa
How many bits in the modulus [512]: 1024
  • Define SSH version to use:
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SW1(config)# ip ssh version 2
  • Enable vty lines to use SSH:
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SW1(config)# line vty 0 4
SW1(config-line)# login local
! You can set vty lines to use only telnet or only ssh or both as in the example.
SW1(config-line)# transport input telnet ssh

Aliases:

Used to create shortcuts for long commands.

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SW1(config)# alias exec c configure terminal
SW1(config)# alias exec s show ip interface brief
SW1(config)# alias exec sr show running-config

Description, speed and duplex:

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SW1(config)# interface fastEthernet 0/1
SW1(config-if)# description LINK TO INTERNET ROUTER
SW1(config-if)# speed 100    ! Options: 10, 100, auto
! The range keyword used to set a group of interfaces at once.
SW1(config)# interface range fastEthernet 0/5 – 10
SW1(config-if-range)# duplex full (options: half, full, auto)

Verify Basic Configuration:

  • Shows information about the switch and its interfaces, RAM, NVRAM, flash, IOS, etc.
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SW1# show version
  • Shows the current configuration file stored in DRAM.
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SW1# show running-config
  • Shows the configuration file stored in NVRAM which is used at first boot process.
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SW1# show startup-config
  • Lists the commands currently held in the history buffer.
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SW1# show history
  • Shows an overview of all interfaces, their physical status, protocol status and ip address if assigned.
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SW1# show ip interface brief
  • Shows detailed information about the specified interface, its status, protocol, duplex, speed, encapsulation, last 5 min traffic.
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SW1# show interface vlan 1
  • Shows the description of all interfaces
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SW1# show interfaces description
  • Shows the status of all interfaces like connected or not, speed, duplex, trunk or access vlan.
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SW1# show interfaces status
  • Shows the public encryption key used for SSH.
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SW1# show crypto key mypubkey rsa
  • Shows information about the leased IP address (when an interface is configured to get IP address via a dhcp server)
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SW1# show dhcp lease

 

 

Configuring port security:

  • Make the switch interface as access port:
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SW1(config-if)# switchport mode access
  • Enable port security on the interface:
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SW1(config-if)# switchport port-security
  • Specify the maximum number of allowed MAC addresses:
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SW1(config-if)# switchport port-security maximum 1
  • Define the action to take when violation occurs:
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SW1(config-if)# switchport port-security violation shutdown    ! options: shutdown, protect, restrict
  • Specify the allowed MAC addresses:

The sticky keyword is used to let the interface dynamically learns and configures the MAC addresses of the currently connected hosts.

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SW1(config-if)# switchport port-security mac-address 68b5.9965.1195    ! options: H.H.H, sticky

Verify and troubleshoot port security:

  • Shows the entries of the mac address table:
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SW1# show mac-address-table
  • Overview of port security of all interfaces:
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SW1# show port-security
  • Shows detailed information about port security on the specified interface:
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SW1# show port-security interface fa0/5

Configuring VLANs:

  • Create a new VLAN and give it a name:
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SW1(config)# vlan 10
SW1(config-vlan)# name SALES
  • Assign an access interface to access a specific VLAN:
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SW1(config)# interface fastEthernet 0/5
SW1(config-if)# switchport mode access
SW1(config-if)# switchport access vlan 10

Configuring an auxiliary VLAN for cisco IP phones:

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SW1(config)# interface fastEthernet 0/5
! accessing vlan 10 (data) and 12 (VoIP)
SW1(config-if) #switchport access vlan 10
SW1(config-if) #switchport voice vlan 12

Configuring Trunks:

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SW1(config)# interface fastEthernet 0/1
SW1(config-if)# switchport mode trunk    ! options: access, trunk, dynamic auto, dynamic desirable
SW1(config-if)# switchport trunk allowed vlan add 10    ! options: add, remove, all, except

Securing VLANs and Trunking:

  • Administratively disable unused interfaces:
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SW1(config-if)# shutdown
  • Prevent trunking by disabling auto negotiation on the interface:
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SW1(config-if)# nonegotiate    ! or hardcode the port asan access port
SW1(config-if)# switchport mode access
  • Assign the port to an unused VLAN:
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SW1(config-if)# switchport access vlan 222

Configuring VTP:

  • Configure VTP mode:

The transparent VTP mode is used when an engineer wants to deactivate VTP on a particular switch

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SW1(config)# vtp mode server    ! options: server, client, transparent
  • Configure VTP domain name:
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SW1(config)# vtp domain EXAMPLE    ! case-sensitive
  • Configure VTP password (optional):
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SW1(config)# vtp password cisco    ! case-sensitive
  • Configure VTP pruning (optional):
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SW1(config)# vtp pruning    ! only works on VTP servers
  • Enable VTP version 2 (optional):
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SW1(config)# vtp version 2

Verify and troubleshoot VLANs and VTP:

  • Lists information about administrative setting and operation status of interface:
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SW1# show interfaces if switchport
  • Lists all the trunk ports on a switch including the trunk allowed VLANs:
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SW1# show interfaces trunk
  • Lists information about the VLANs:
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SW1# show vlan {brief | id | name | summary}
  • Lists VTP configuration (mode, domain-name, version, etc) and revision number:
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SW1# show vtp status
  • Shows the VTP password:
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SW1# show vtp password

STP optimization:

  • Hard coding the root bridge (changing bridge priority):
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SW1(config)# spanning-tree vlan 1 root primary
SW1(config)# spanning-tree vlan 1 root secondary
! Priority must be a multiply of 4096
SW1(config)# spanning-tree [vlan 1]priority 8192
  • Changing the STP mode:
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SW1(config)# spanning-tree mode rapid-pvst    ! options: mst, pvst, rapid-pvst
  • Enabling portfast and BPDU guard on an interface:

Portfast and BPDU guard are enabled only on interfaces connected to end user hosts

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SW1(config-if)# spanning-tree portfast
SW1(config-if)# spanning-tree bpduguard enable
  • Changing port cost:
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SW1(config-if)# spanning-tree [vlan 1] cost 25
  • Bundling interfaces into an etherchannel:
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SW1(config-if)# channel-group 1 mode on    ! options: auto, desirable, on

STP verification and troubleshooting:

  • Shows detailed info about STP state:
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SW1# show spanning-tree
  • Shows STP info only on a specific port:
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SW1# show spanning-tree interface fa0/2
  • Shows STP info only for a specific VLAN:
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SW1# show spanning-tree vlan 1
  • Shows info about the root switch:
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SW1# show spanning-tree [vlan 1] root
  • Shows info about the local switch:
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SW1# show spanning-tree [vlan 1] bridge
  • Show the state of the etherchannels:
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SW1# show etherchannel 1
  • Provides informational messages about the changes in the STP topology:
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SW1# debug spanning-tree events

Enabling or disabling CDP:

  • Enabling CDP globally on a switch:
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SW1(config)# cdp run
  • Disabling CDP on a given interface:
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SW1(config-if)# no cdp enable

Using CDP for network verification and troubleshooting:

  • Shows global information about CDP itself:
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SW1# show cdp
  • Shows information about CDP on a specific interface:
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SW1# show cdp interface fa0/2
  • Shows information about the directly connected cisco devices including interfaces names capabilities:
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SW1# show cdp neighbors
  • Shows detailed information about the neighboring cisco devices including device address and version of IOS they run:
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SW1# show cdp neighbors detail
! OR
SW1# show cdp entry *
  • Shows detailed information about the specified entry only:
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SW1# show cdp entry SW2

 

 

Router basic configuration:

This section includes IOS commands that are absolutely identical on both routers and switches, except the part of line aux 0 which is configured only on router because switches do not have an auxiliary port.

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Router(config)# hostname R1
R1(config)# enable secret cisco
R1(config)# line con 0
R1(config-line)# password cisco
R1(config-line)# login
R1(config-line)# logging synchronous
R1(config-line)# exec-timeout 30 0
R1(config-line)# exit
R1(config)# line vty 0 4
R1(config-line)# password cisco
R1(config-line)# login
R1(config-line)# logging synchronous
R1(config-line)# exec-timeout 30 0
R1(config-line)# exit
R1(config)# line aux 0
R1(config-line)# password cisco
R1(config-line)# login
R1(config-line)# logging synchronous
R1(config-line)# exec-timeout 30 0
R1(config-line)# exit
R1(config)# banner motd $
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
UNAUTHORIZED ACCESS IS PROHIBITED
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
$
R1(config)# alias exec c configure terminal
R1(config)# alias exec s show ip interface brief
R1(config)# alias exec sr show running-config
R1(config)# no ip domain-lookup
R1(config)# service password-encryption
R1(config)# ip domain-name example.com
R1(config)# username admin password cisco
R1(config)# crypto key generate rsa
How many bits in the modulus [512]: 1024
R1(config)# ip ssh version 2
R1(config)# line vty 0 4
R1(config-line)# login local
R1(config-line)# transport input telnet ssh

Configuring router interfaces:

Clock rate is set only on the DCE side, typically the ISP side. On your router which is DTE you don’t need to set clocking.

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R1(config)# interface fastEthernet 0/0
R1(config-if)# description LINK TO LOCAL LAN THROUGH SW1
R1(config-if)# ip address 172.16.1.1 255.255.255.0
R1(config-if)# no shutdown
R1(config-if)# exit
R1(config)# interface serial 0/1/0
R1(config-if)# description WAN CONNECTION TO R2
R1(config-if)# ip address 10.1.1.1 255.255.255.252
R1(config-if)# clock rate 128000
R1(config-if)# no shutdown

Configuring Router-On-Stick for vlan routing:

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R1(config)# interface fastEthernet 0/0
R1(config-if)# no shutdown
R1(config)# interface fastEthernet 0/0.10
R1(config-subif)# encapsulation dot1q 10
R1(config-subif)# ip address 192.168.10.1 255.255.255.0
R1(config-subif)# interface fastEthernet 0/0.20
R1(config-subif)# encapsulation dot1q 20
R1(config-subif)# ip address 192.168.20.1 255.255.255.0

Static route:

  • Using next hop:
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R1(config)# ip route 10.1.2.0 255.255.255.0 10.1.128.1
  • Using exit interface:
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R1(config)# ip route 10.1.2.0 255.255.255.0 Serial 0/0
*Note: Exit interface can be used in point-to-point serial links.

Default Route:

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R1(config)# ip route 0.0.0.0 0.0.0.0 199.1.1.1

RIPv2 Configuration:

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R1(config)# router rip
R1(config-router)# version 2
R1(config-router)# network 10.0.0.0    ! written as an original class A
R1(config-router)# no auto-summary
R1(config-router)# passive-interface serial 0/0

RIPv2 Verification:

  • Shows information about the running routing protocol process:
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R1# show ip protocols
  • Shows the entire routing table:
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R1# show ip route
  • Shows routes learned via RIP only:
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R1# show ip route rip
  • Shows detailed information about the route to the specified destination network:
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R1# show ip route 10.1.1.1

OSPF Configuration:

  • Enter OSPF router configuration mode:
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R1(config)# router ospf 10    ! 10 = process ID
  • Configure one or more network commands to identify which interfaces will run OSPF:
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R1(config-router)# network 10.0.0.0 0.255.255.255 area 0
R1(config-router)# network 172.16.8.0 0.0.7.255 area 0
R1(config-router)# network 192.168.1.254 0.0.0.0 area 1
  • Configure router ID either (Optional):

Using router-id ospf subcommand:

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R1(config-router)# router-id 1.1.1.1

Configuring an IP address on a loopback interface:

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R1(config)# interface loopback 0
R1(config-if)# ip address 1.1.1.1 255.255.255.255
  • Change Hello and Dead intervals per interface (Optional):
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R1(config-if)# ip ospf hello-interval 2
R1(config-if)# ip ospf dead-interval 6
  • Impact routing choices by tuning interface cost using one of the following ways (Optional):

Changing interface cost:

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R1(config-if)# ip ospf cost 55

Changing interface bandwidth:

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R1(config-if)# bandwidth 128    ! in Kbps

Changing the reference bandwidth that used by OSPF to calculate the cost:

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R1(config-router)# auto-cost reference-bandwidth 1000    ! in Mbps
  • Disabling OSPF on a certain interface (Optional):
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R1(config-router)# passive-interface serial 0/0
  • Configuring OSPF authentication (Optional):

Type 0 authentication (none):

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R1(config-if)# ip ospf authentication null

Type 1 authentication (clear text):

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R1(config-if)# ip ospf authentication
R1(config-if)# ip ospf authentication-key cisco

Type 2 authentication (md5):

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R1(config-if)# ip ospf authentication message-digest
R1(config-if)# ip ospf message-digest-key 1 md5 cisco
  • Configure maximum equal-cost paths (Optional):
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R1(config-router)# maximum paths 6

OSPF verification:

  • Shows information about the running routing protocol process:
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R1# show ip protocols
  • Shows the entire routing table:
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R1# show ip route
  • Shows routes learned via OSPF only:
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R1# show ip route ospf
  • Shows all neighboring routers along with their respective adjacency state:
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R1# show ip ospf neighbors
  • Shows all the information contained in the LSDB:
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R1# show ip ospf database
  • Shows detailed information about OSPF running on a specific interface:
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R1# show ip ospf interfaces serial 0/0

EIGRP Configuration:

  • Enter EIGRP configuration mode and define AS number:
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R1(config)# router eigrp 121    ! 121 = AS number
  • Configure one or more network commands to enable EIGRP on the specified interfaces:
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R1(config-router)# network 10.0.0.0
R1(config-router)# network 172.16.0.0 0.0.3.255
R1(config-router)# network 192.168.1.1 0.0.0.0
R1(config-router)# network 0.0.0.0 255.255.255.255
  • Disable auto summarization (Optional):
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R1(config-router)# no auto-summary
  • Disable EIGRP on a specific interface (Optional):
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R1(config-router)# passive-interface serial 0/0
  • Configure load balancing parameters (Optional):
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R1(config-router)# maximum-paths 6
R1(config-router)# variance 4
  • Change interface Hello and Hold timers (Optional):
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R1(config-if)# ip hello-interval eigrp 121 3
R1(config-if)# ip hold-time eigrp 121 10
  • Impacting metric calculations by tuning BW and delay of the interface (Optional):
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R1(config-if)# bandwidth 265    ! in Kbps)
R1(config-if)# delay 120    ! tens of microseconds

EIGRP Authentication:

The key-string value and the mode must be the same on both routers. Lifetime options of the keys requires the clock of the routers to be set correctly, better use NTP, or it can cause problems

  • Create an authentication key chain as follows:

Create a key chain and give it a name:

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R1(config)# key chain MY_KEYS

Create one or more keys giving them numbers:

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R1(config-keychain)# key 1

Define the key value:

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R1(config-keychain-key)# key-string1stKEY

Define the life time of the keys (optional):

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R1(config-keychain-key)# send-lifetime [start time] [end time]
R1(config-keychain-key)# accept-lifetime [start time] [end time]
  • Enable md5 authentication mode for EIGRP on the interface:
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R1(config-if)# ip authentication mode eigrp121 md5
  • Refer to the correct key chain to be used on the interface:
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R1(config-if)# ip authentication key-chain eigrp121 MY_KEYS

EIGRP Verification:

  • Shows routes learned via EIGRP only:
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R1# show ip route eigrp
  • Shows EIGRP neighbors and status:
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R1# show ip eigrp neighbors
  • Shows EIGRP topology table, including successor and feasible successor:
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R1# show ip eigrp topology
  • Shows interfaces that run EIGRP:
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R1# show ip eigrp interfaces
  • Lists statistics on numbers of EIGRP messages sent and received by the router:
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R1# show ip eigrp traffic

 

 

Access Control Lists:

Standard ACL: 1 – 99 and 1300 – 1999

  • Use a remark to describe the ACL (Optional):
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R1(config)# access-list 1 remark ACL TO DENY ACCESS FROM SALES VLAN
  • Create the ACL, keeping the following in mind:
    • ACL uses first-match logic.
    • There is an implicit deny anyat the end of the ACL.
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R1(config)# access-list 2 deny 192.168.1.77
R1(config)# access-list 2 deny 192.168.1.64 0.0.0.31
R1(config)# access-list 2 permit 10.1.0.0 0.0.255.255
R1(config)# access-list 2 deny 10.0.0.0 0.255.255.255
R1(config)# access-list 2 permit any
  • Enable the ACL on the chosen router interface in the correct direction (in or out):
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R1(config-if)# ip access-group 2 out
  • Using standard ACL to limit telnet and SSH access to a router:

Create the ACL that defines the permitted telnet clients:

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R1(config)# access-list 99 remark ALLOWED TELNET CLIENTS
R1(config)# access-list 99 permit 192.168.1.128 0.0.0.15

Apply the ACL inbound the vty lines

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R1(config)# line vty 0 4
R1(config-line)# access-class 99 in

Extended ACL: 100 – 199 and 2000 – 2699

  • Extended ACL should be placed as close as possible to the source of the packet.
  • Extended ACL matches packets based on source & des.IP addresses, protocol, source & des. Port numbers andother criteria as well
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R1(config)# access-list 101 remark MY_ACCESS_LIST
R1(config)# access-list 101 deny iphost 10.1.1.1 host 10.2.2.2
R1(config)# access-list 101 deny tcp 10.1.1.0 0.0.0.255 any eq 23
R1(config)# access-list 101 deny icmp 10.1.1.1 0.0.0.0 any
R1(config)# access-list 101 deny tcphost 10.1.1.0 host 10.0.0.1 eq 80
R1(config)# access-list 101 deny udphost 10.1.1.7 eq 53 any
R1(config)# access-list 101 permit ip any any
R1(config)# interface fastEthernet 0/0
R1(config-if)# ip access-group 101 in

Named ACL:

  • Named ACLs use names to identify ACLs rather than numbers, and commands that permit or deny traffic are written in a sub mode called named ACL mode (nacl).
  • Named ACL enables the editing of the ACL (deleting or inserting statements) by sequencing statements of the ACL.
  • Named standard ACL:
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R1(config)# ip access-list standard MY_STANDARD_ACL
R1(config-std-nacl)# permit 10.1.1.0 0.0.0.255
R1(config-std-nacl)# deny 10.2.2.2
R1(config-std-nacl)# permit any
R1(config)# interface fastEthernet 0/1
R1(config-if)# ip access-group MY_STANDARD_ACL out
  • Named extended ACL:
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R1(config)# ip access-list extended MY_EXTENDED_ACL
R1(config-ext-nacl)# deny icmp 10.1.1.1 0.0.0.0 any
R1(config-ext-nacl)# deny tcphost 10.1.1.0 host 10.0.0.1 eq 80
R1(config-ext-nacl)# permit ip any any
R1(config)# interface fastEthernet 0/1
R1(config-if)# ip access-group MY_EXTENDED_ACL in
  • Editing ACL using sequence numbers:
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R1(config)# ip access-list extended MY_EXTENDED_ACL
R1(config-ext-nacl)# no 20    ! Deletes the statement of sequence number 20
R1(config)# ip access-list standard 99
R1(config-std-nacl)# 5 deny 1.1.1.1    ! inserts a statement with sequence 5

Verifying ACLs:

  • Shows all ACLs configured on a router with counters at the end of each statement:
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R1# show access-lists
! OR
R1# show ip access-list
  • Shows only the specified ACL:
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R1# show ip access-list 101
  • Includes a reference to the ACLs enabled on that interface either in or out:
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R1# show ip interface f0/0

DHCP Server

  • Define a DHCP pool and give it a name:
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R1(config)# ip dhcp pool MY_POOL
  • Define network and mask to use in this pool and the default gateway:
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R1(dhcp-config)# network 192.168.1.0 255.255.255.0
R1(dhcp-config)# default-router 192.168.1.1
  • Define one or more DNS server (OPTIONAL):
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R1(dhcp-config)# dns-server 213.131.65.20 8.8.8.8
  • Confine the lease time (OPTIONAL):
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R1(dhcp-config)lease 2    ! Days
  • Define one or more scopes of excluded (reserved) addresses (OPTIONAL):
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R1(config)# ip dhcp excluded-address 192.168.1.1 192.168.1.100
R1(config)# ip dhcp excluded-address 192.168.1.200 192.168.1.254

DHCP Verification and Troubleshooting:

  • Shows the status of the specified pool and the leased addresses from that pool:
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R1# show ip dhcp pool POOL_1
  • Shows all the leased ip addresses from all configured DHCP pools:
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R1# show ip dhcp binding
  • Shows any conflicts that occurred:
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R1# show ip dhcp conflict

 

 

PPP Configuration:

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R1(config)# interface serial 0/0
R1(config-if)# encapsulation ppp

PPP Authentication:

CHAP:

  • Configure the hostname:
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R1(config)# hostname ALPHA
  • Configure the name of the other end router and the shared password:
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! The password used is shared password, that means it must be the same on both routers
ALPHA(config)# username BETA password XYZ
  • Enable CHAP authentication on the interface:
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ALPHA(config)# interface serial 0/0
ALPHA(config-if)# ppp authentication chap

PAP:

  • Configure the hostname:
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R1(config)# hostname ALPHA
  • Configure the name of the other end router and the shared password:
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ALPHA(config)# username BETA password XYZ
  • Enable PAP authentication on the interface and define the username and password to be sent by PAP:
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ALPHA(config)# interface serial 0/0
ALPHA(config-if)# ppp authentication pap
ALPHA(config-if)# ppp pap sent-username ALPHA password XYZ

PPP Verification and troubleshoot:

  • Shows the encapsulation type and the control protocols of PPP:
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R1# show interface s0/0
  • Useful for viewing the configuration of usernames and passwords used to authenticate PPP:
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R1# show running-config
  • Displays the authentication process of PPP in real time:
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R1# debug ppp authentication

Frame Relay:

Multipoint (one subnet)

  • Give the interface an ip address and enable Frame Relay encapsulation:
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R1(config)# interface serial 0/0
R1(config-if)# ip address 1.1.1.1 255.255.255.0
R1(config-if)# encapsulation frame-relay (ietf)
  • Configure LMI signaling type: (Optional as discussed with ISP):
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R1(config-if)# frame-relay lmi-type ansi    ! options: ansi, cisco, q933a
  • Configure Frame Relay mapping:
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R1(config-if)# frame-relay map ip 1.1.1.2 102 broadcast (ietf)
R1(config-if)# frame-relay map ip 1.1.1.3 103 broadcast
R2(config)# interface serial 0/0
R2(config-if)# ip address 1.1.1.2 255.255.255.0
R2(config-if)# encapsulation frame-relay
R2(config-if)# frame-relay map ip 1.1.1.1 201 broadcast
R2(config-if)# frame-relay map ip 1.1.1.3 201 broadcast
R3(config)# interface serial 0/0
R3(config-if)# ip address 1.1.1.3 255.255.255.0
R3(config-if)# encapsulation frame-relay
R3(config-if)# frame-relay map ip 1.1.1.1 301 broadcast
R3(config-if)# frame-relay map ip 1.1.1.2 301 broadcast

Point-to-point (different subnets; one subnet per subinterface)

  • Enable Frame Relay encapsulation:
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R1(config)# interface serial 0/0
R1(config-if)# encapsulation frame-relay
  • Give an ip address to a subinterface and configure its DLCI:
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R1(config)# interface serial 0/0.102 point-to-point
R1(config-subif)# ip address 1.1.1.1 255.255.255.0
R1(config-subif)# frame-relay interface-dlci 102
R1(config)# interface serial 0/0.103 point-to-point
R1(config-subif)# ip address 2.2.2.1 255.255.255.0
R1(config-subif)# frame-relay interface-dlci 103
R2(config)# interface serial 0/0
R2(config-if)# encapsulation frame-relay
R2(config)# interface serial 0/0.201 point-to-point
R2(config-subif)# ip address 1.1.1.2 255.255.255.0
R2(config-subif)# frame-relay interface-dlci 201
R3(config)# interface serial 0/0
R3(config-if)# encapsulation frame-relay
R3(config)# interface serial 0/0.301 point-to-point
R3(config-subif)# ip address 2.2.2.2 255.255.255.0
R3(config-subif)# frame-relay interface-dlci 301

Frame Relay Verification and troubleshoot:

  • Shows the encapsulation type:
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R1# show interfaces serial 0/0
  • Lists PVC status information:
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R1# show frame-relay pvc
  • Lists DLCI to IP mapping:
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R1# show frame-relay map
  • Lists LMI status information:
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R1# show frame-relay lmi
  • Displays the content of LMI messages:
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R1# debug frame-relay lmi
  • Lists messages about certain Frame Relay events, including Inverse ARP messaeges:
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R1# debug frame-relay events

Network Address Translation (NAT):

Static NAT:

  • Define the outside and inside interfaces:
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R1(config)# interface serial 0/0
R1(config-if)# ip nat outside
R1(config)# interface FastEthernet 1/1
R1(config-if)# ip nat inside
  • Configure static NAT statement:
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R1(config)# ip nat inside source static 192.168.1.10 200.1.1.1

Dynamic NAT:

  • Define the outside and inside interfaces
  • Create an ACL that determines the IP addresses thatare allowed to be translated:
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R1(config)# access-list 3 permit 192.168.1.0 0.0.0.255
  • Create a pool of public IP addresses:
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R1(config)# ip nat pool PUB 200.1.1.1 200.1.1.6 netmask 255.255.255.248
  • Configure NAT statement:
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R1(config)# ip nat inside source list 3 pool PUB</pre>
<h4>NAT Overload (PAT):</h4>
<ul>
<li>The same as dynamic NAT with the use of the overload keyword at the end of NAT statement:</li>
</ul>
<pre>
R1(config)# ip nat inside source list 3 pool PUB overload

NAT verification and troubleshoot:

  • Useful in viewing the configuration of NAT pool and the inside and outside interfaces:
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R1# show running-config
  • Displays access lists, including the one used for NAT:
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R1# show access-lists
  • Shows counters for packets and NAT table entries, as well as basic configuration information:
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R1# show ip nat stasitics
  • Displays the NAT table:
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R1# show ip nat translations
  • Clears all the dynamic entries in the NAT table:
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R1# clear ip nat translations *
  • Issues a log message describing each packet whose ip address is translated with NAT:
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R1# debug ip nat