| By Sheldon L | Published at 2020-05-09 | Updated at 2020-05-09 |
show version
show running-config
sh start
copy running-config startup-config
! There are now so many options you can use, check
copy running-config ?
! Make a second backup
copy running-config tftp
! Restore
copy tftp running-config
! NOTE: the interfaces are shut down by default and you must manually enable each interface
! Erase
erase startup-config
reload
!
! Gateway Router
Router(config)# interface Ga0/0/0
Router(config-if)# ip address 192.168.1.1 255.255.255.0
Router(config-if)# no shutdown
!
! Switch
Switch(config)# ip dhcp excluded-address 192.168.1.1 192.168.1.100
Switch(config)# ip dhcp pool IT_Support
Switch(dhcp-config)# network 192.168.1.0 255.255.255.0
Switch(dhcp-config)# default-router 192.168.1.1
Switch(dhcp-config)# dns-server 192.168.1.1
Switch(config)# interface vlan 1
Switch(config-if)# ip address 192.168.1.2 255.255.255.0
Switch(config-if)# no shutdown
Switch(config-if)# exit
! OPTIONAL:
! set the lease time in days, hours, and minutes.
! Default lease time is 24h.
Switch(dhcp-config)# lease 3 12 17
! OPTIONAL:
! set option 66, which is sending a TFTP server address to a DHCP client.
! This is typically used for VoIP phones, or auto installs, and needs to be listed as a FQDN.
Switch(dhcp-config)# option 66 ascii tftp.somewhere.com
! configure the Fa0/0 interface of the router
! to accept the DHCP client requests (broadcast)
! and forward them to the DHCP server (unicast)
Router# config t
Router(config)# interface Fa0/0
Router(config-if)# ip helper-address 10.10.10.254
! Lists state information about each IP address currently leased to a client.
show ip dhcp binding
! Lists the configured range of IP addresses,
! plus statistics for the number of currently leased addresses
! and the high watermark for leases from each pool.
show ip dhcp pool [poolname]
! Lists DHCP server statistics
show ip dhcp server statistics
! Check duplicate address
show ip dhcp conflict
If you want to use a hostname instead of an IP address to connect to a remote device, the device that you’re using to make the connection must be able to translate the hostname to an IP address.
SW-1# config t
SW-1(config)# ip host SW-2 ?
<0-75537> Default telnet port number
A.B.C.D Host IP address
additional Append addresses
SW-1(config)# ip host SW-2 10.100.128.9
SW-1(config)# ip host SW-3 10.100.128.8
SW-1(config)# do sho hosts
! Try to telnet
SW-1# sw-3
SW-3> Ctrl+Shift+6
SW-1#
SW-1# sh sessions
! Remove IP host
SW-1(config)# no ip host SW-3
SW-1# config t
SW-1(config)# ip domain-lookup
! In case of it is turned off. It is turned on by default.
! Sets the IP address of the DNS server
SW-1(config)# ip name-server 4.4.4.4
! OPTIONAL:
! the hostname will followed by domain name.
SW-1(config)# ip domain-name lammle.com
SW-1(config)# ^Z
! Try to ping, if you added SW-3 in DNS server
SW-1#ping SW-3
enable
configure terminal
enable secret hope
line console 0
login
! This login will remind you if password is not set
password love
login
! This login means need password to login
exit
line console 0
no login
! no login means password may exist but is not needed when login
exit
line console 0
login local
! login local means login with username and secret
username sheldon secret love
no password
! no password disable plain password
! ecrypt plain password and show config
service password-encryption
show running-config
line vty ?
line vty 0 15
! the same as line console
! ssh
hostname S1
ip domain-name ccna.com
crypto key generate rsa modulus 1024
ip ssh version 2
line vty 0 15
transport input ssh
login local
exec-timeout ?
exit
! before login from remote
Router(config)#interface Ga0/0/0
Router(config-if)#ip address 192.168.1.1 255.255.255.0
Switch(config)# ip dhcp excluded-address 192.168.1.1 192.168.1.100
Switch(config)# ip dhcp pool IT_Support
Switch(dhcp-config)# network 192.168.1.0 255.255.255.0
Switch(dhcp-config)# default-router 192.168.1.1
Switch(dhcp-config)# dns-server 192.168.1.1
Switch(config)# interface vlan 1
Switch(config-if)# ip address 192.168.1.2 255.255.255.0
Switch(config-if)# no shutdown
Switch(config-if)# exit
! login from PC (DHCP set)
ssh -l [username] [secret]
S1>
S1#
S1(config)#
! Entering different interfaces in config mode
interface [type] [number]
interface vlan 1
ip dhcp pool [name]
ip access-list standard [name]
exit
end
disable
logout
! history
show history
show terminal
terminal history size
! do show in configuration mode
do show run # to view the configuration and statistics from within configuration mode
! Viewing, Saving
show startup-config
show running-config
copy running-config ?
copy running-config startup-config
! Cisco Discovery Protocol (CDP)
! get the Network layer addresses you need for pinging
show cdp entry *
show interfaces [interface]
clear counters [interface]
show interfaces
show interfaces status
show interfaces description
show protocols # Layer 1 and layer 2
! Add interfaces to a new VLAN, enable both data and voic
vlan 2
name USERs
exit
interface range Fa 0/11-24
switchport access vlan 2
switchport mode trunk
switchport voice vlan 2
no shutdown
end
show interfaces switchport
! connect channel-group to another switch, using F0/21-24
interface range Fa 0/21-24
channel-group [number] mode on
! do the same on the other switch
show interfaces switchport
show interfaces Fa 0/11 switchport
show interfaces trunk
show interfaces Fa 0/11 trunk
! If a trunk (or access) port, all trunk (or access), it's trunk (or access) VLAN
! If a trunc VLAN, the native VLAN
interface range Fa 0/21-24
switchport trunk allowed vlan 2
! STP interface settings
pvst
rapid-pvst
mst
! Connecting to multiple devices
SW-3> Ctrl+Shift+6
! then press X
! Check sessions
SW-1# sh sessions
! Asterisk (*) means that was the last session connected to,
! you can return to your last session by pressing Enter twice
! Check users
SW-1# sh users
! Disconnect
SW-3>exit
SW-1# disconnect ?
SW-1# disconnect 2
! Message of the day (MOTD)
banner motd #
! Enter TEXT message. End with the character '#'
$ Acme.com network, then you must disconnect immediately.#
! This MOTD banner essentially tells anyone connecting to the device
! to get lost if they’re not on the guest list
banner motd x Unauthorized access prohibited! x
ping # Uses ICMP echo request and replies to test if a node IP stack is initialized and alive on the network.
! If you want to use a different diagnostic port,
! you can create a logical interface called a loopback
interface loopback ?
ip address 20.20.20.1 255.255.255.0
ping # Source address or interface: 20.20.20.1
telnet
terminal monitor # To allow console messages to be sent to your Telnet session
traceroute | tracert # Displays the list of routers on a path to a network destination by using TTL time-outs and ICMP error messages.
arp -a | show ip arp # Displays IP-to-MAC-address mappings
ipconfig /all # shows you the PC network configuration.
ipconfig getifaddr en0 # Used to find your IP address
ifconfig # Used to get the IP address details
curl ifconfig.me # display your global Internet IP address
curl ipecho.net/plain ; echo # display your global Internet IP address
ping 127.0.0.1 # local host, IP stack is considered initialized
ping [self-address] # local host IP, NIC is functioning, but cable is not considered
ping [default-gateway] # Local physical link is OK
ping [remote-server] # Remote server is working
# If above woks, but still can't communicate with remote server, check DNS
host
dig
nslookup
traceroute
ifconfig # work on PC
arp -a # work on PC
show ip arp # work on Cisco IOS
debug all can severely diminish the router’s performance—even render it unusable! Always best to use more specific debug commands.SW-1> en
SW-1# debug ?
SW-1# no debug all
! OR
SW-1# undebug all
! Open IP ICMP debugging mode
SW-1# debug ip icmp
! Try
SW-1# ping 192.168.10.17
show processes CommandSW-1# sh processes
show ip interface
show ip interface brief
show protocols [type] [number]
show interfaces [type] [number]
show interfaces
show ip route
show interfaces trunk
show interfaces [type] [number] trunk
show interfaces switchport
show interfaces [type] [number] switchport
show controllers # DCE/DTC cable