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Cisco Routers

Cisco Routers

Cisco Routers Commands

Enable commands

  • en

Show MAC address table

  • show mac-address-table

Show VLAN Information

  • show vlan brief

Show IP address assignments and status of interfaces

  • show ip interface brief

Show DHCP info

  • show ip dhcp pool

Show which IP addresses are associated with which MAC addresses

  • show ip dhcp binding

Show DHCP errors / IP conflicts

  • show ip dhcp conflict

Show NAT translation table

  • show ip nat translations
  • show ip nat statistics

Show ARP cache

  • show arp

Clear arp cache

  • clear arp-cache

Put into config mode

  • conf t

Create VLAN

  • vlan
  • name
  • exit

Configure VLAN

  • interface range Gig
  • switchport mode access
  • switchport access vlan
  • end

Show interfaces command - shows trunks

  • show interfaces trunk

Configure Trunk

  • interface gig
  • switchport trunk encapsulation dot1q
  • switchport mode trunk
  • end

Write command - write config to memory to keep changes after reboot

  • wr

shutdown port

  • conf t
  • int
  • g
  • shutdown

Enable port

  • conf t
  • int
  • g
  • no shutdown

Port mirroring

  • monitor session source int g
  • monitor session destination int g

Show IP Routes

  • show iproute

Configure route

  • conf t
  • ip route

Copy running config to flash memory

  • copy run flash

VPN Commands

Check status of VPN

Phase 1:

1
show crypto isakmp sa

Phase 2

1
show crypto ipsec sa

Verify Crypto Map Configuration:

1
show crypto map

Check active connections:

1
show crypto engine connections active

Change peer IP of VPN

To change the peer of a configured VPN you will need to enable the configuration in the terminal

1
2
enable
configure terminal

Then you will need to select the VPN tunnel to change:

1
2
crypto map  10 ipsec-isakmp
set peer 

You will need to update the shared key used for connections to the new peer ip:

1
crypto isakmp key  address 

You will also need to remove the previous peer IP from the crypto map:

1
2
crypto map  10 ipsec-isakmp
no set peer 

DNS Commands

To setup a Router as a DNS Client:

  • ip domain-lookup
  • ip name-server
  • ip domain-name
  • ip domain-list

To setup as a server use these commands additionally:

  • ipdns server
  • ip host