Cisco: To clear the configuration, use: erase startup-config (which deletes the contents of NVRAM), then reboot the router with: reload.

Huawei: To clear the configuration, use: reset saved-configuration, then reboot the router with: reboot.

Cisco Router and Switch Password Recovery:

Selective Routing Advertisement:

For example, in RIP configuration, configure the S0 interface to only receive but not send RIP advertisements.

Router(config)#router rip
Router(config-router)#passive-interface serial 0

About Keyboard Shortcuts:

• Ctrl+B (backward): Move the cursor one character to the left.
• Ctrl+F (forward): Move the cursor one character to the right.
• Ctrl+A (A stands for "beginning"): Move the cursor to the beginning of the command.
• Ctrl+E (end): Move the cursor to the end of the command.
• Esc+B (backward): Move the cursor one word to the left.
• Esc+F (forward): Move the cursor one word to the right.
• Ctrl+Z: Exit privileged mode at once (Router#).

About Modes:

• User Mode (User Execution Mode): The initial mode when connecting to a router, characterized by the ">" prompt. In this mode, you can only view the configuration and status of the router but cannot make changes. To configure the router, you must enter Privileged Mode.
• Privileged Mode (Privilege Execution Mode): To enter this mode, use the command enable. If a password is set, you will need to enter the correct password. This mode is characterized by the "#" prompt.
• Global Configuration Mode: From Privileged Mode, you can enter this mode by using the command configure terminal. In this mode, you can make global configurations.
• Specific Configuration Modes: These include router interface configuration mode, router sub-interface configuration mode, routing protocol configuration mode, line configuration mode, and more.

Mode Transitions:

• After connecting to the router, you first enter User Mode, which is characterized by the ">" symbol. In this mode, you can only view the router's configuration and status, but you cannot configure it.
• To make configurations, you must enter Privileged Mode. Use the command enable to enter, and if a password is set, it must be entered correctly.
• In Privileged Mode, the prompt will change to "#".
• To enter Global Configuration Mode from Privileged Mode, use the command configure terminal.

Commands to Enter Specific Configuration Modes from Global Configuration Mode:

• Privileged Mode → Router Interface Configuration Mode:
  • For serial interface: interface serial ??
  • For Ethernet interface: interface ethernet ??

• Privileged Mode → Router Sub-interface Configuration Mode: subinterface
• Privileged Mode → Routing Protocol Configuration Mode: router rip
• Privileged Mode → Line Configuration Mode: line vty ??

Commands and Usage in Different Modes:

User Mode (Router>):

• show ping, telnet, connect: These commands are used the same way as in Privileged Mode.

Privileged Mode (Router#):

• show users: View all users connected to the router.
• show hosts: View the IP-to-name mapping table.
• show arp: View the ARP (Address Resolution Protocol) table.
• show protocol: View the router's protocol status.
• show version: View the version of the IOS and memory information.
• show flash: View the flash memory usage.
• show clock: View the current time of the router.
• show history: View the last ten commands entered.
• show ip interface brief: View the IP settings and status of router interfaces.
• show interfaces: View the status of all router interfaces.
• show interfaces [specific interface]: View the status of a specific router interface.
• show running-config: View the configuration file in RAM.
• show startup-config: View the configuration file in NVRAM.
• show cdp: View CDP information.
• show cdp entry ??: View information about a specific neighboring router.
• show cdp neighbors: View all neighboring routers.
• show cdp neighbors detail: View detailed information about all neighboring routers.
• show cdp traffic: View information about CDP packets.
• show cdp ?? (port number): View CDP information for a specific port.
• show session: View the status of the original router during a remote login session.
• clear cdp counters: Clear CDP counters.
• clear cdp table: Clear the CDP information.
• copy running-config startup-config: Copy the configuration file in RAM to NVRAM.
• copy startup-config running-config: Copy the configuration file in NVRAM to RAM.
• copy tftp running-config: Copy the configuration file from a TFTP server to RAM.
• copy running-config tftp: Copy the configuration file from RAM to a TFTP server.
• ping ?? (hostname or IP): Test the connectivity between the router and a remote router.
• telnet ?? (hostname or IP): Log in to a remote router (requires login password).
• connect ?? (hostname or IP): Similar to telnet for remote login.
• traceroute ?? (hostname or IP): Trace the route to a destination router.

Commands in Global Configuration Mode:

• hostname ?? (name): Change the router's hostname.
• enable password ??: Change the password for entering Privileged Mode.
• enable secret ??: Change the secret password for entering Privileged Mode (this password is encrypted).
• clock set hour:minute:second day month year: Set the router's time.
• ip host ?? (name) ?? (IP address): Add a hostname-to-IP address mapping.
• service password-encryption: Enable encryption for all passwords (the enable secret password is already encrypted).
• cdp run: Enable CDP (Cisco Discovery Protocol) on all interfaces.
• cdp timer: Set the CDP advertisement timer.
• cdp holdtime: Set the CDP hold time.
• end: Exit from Global Configuration Mode to User Mode.
• exit: Exit one level at a time (use multiple exit commands to progressively step out).

Commands in Interface Configuration Mode:

• ip address ?? (IP address): Set the IP address for the interface.
• no shutdown: Enable the interface (bring it up).
• shutdown: Disable the interface (bring it down).
• clock rate ??: Set the clock rate for the DCE (Data Circuit-Terminating Equipment) side (DTE does not need this).
• cdp enable: Enable CDP (Cisco Discovery Protocol) on the interface.

Commands in Line Configuration Mode:

line vty 0 4
password ??
login: Enable login for the virtual terminal lines using the configured password.

Most Common Cisco Command Categories:

1. Switch Configuration Commands:

Mode Transition Commands:

• User Mode → Privileged Mode: Use the command enable.
• Privileged Mode → Global Configuration Mode: Use the command config t.
• Global Configuration Mode → Interface Mode: Use the command interface [interface type] [interface number].
• Global Configuration Mode → Line Configuration Mode: Use the command line [interface type] [interface number].

Note:

• User Mode: Used to view initialization information.
• Privileged Mode: Used to view all information, debug, and save configuration information.
• Global Configuration Mode: Used to configure overall settings for the router or switch, affecting all interfaces.
• Interface Mode: Used to configure settings for a specific interface.
• Line Configuration Mode: Used to configure control settings for the router's interfaces.

Configuration Commands:

• show running-config: Display all configurations.
• show version: Display version number and register values.
• shutdown: Disable the interface.
• no shutdown: Enable the interface.
• ip address [IP address]: Configure an IP address for the interface.
• secondary [IP address]: Configure a secondary IP address for the interface.
• show interface [interface type] [interface number]: View the interface status and configuration.
• show controllers [interface]: Check if the interface has a DCE cable connected.
• show history: View the history of commands entered.
• show terminal: View terminal settings, including terminal buffer size.
• hostname [hostname]: Configure the router or switch hostname.
• config memory: Modify the startup configuration saved in NVRAM.
• exec-timeout 0 0: Set the console session timeout to zero (no timeout).
• service password-encryption: Encrypt all passwords manually.
• enable password [password]: Configure a plaintext password for Privileged Mode.
• enable secret [password]: Configure a secret (encrypted) password for Privileged Mode.
• line vty 0 4/15: Enter the configuration mode for telnet lines.
• password [password]: Configure a password for telnet access.
• line aux 0: Enter the configuration mode for the AUX (Auxiliary) port.
• password [password]: Configure a password for the AUX port.
• line con 0: Enter the configuration mode for the console port.
• password [password]: Configure a password for the console port.
• bandwidth [number]: Configure the bandwidth for an interface.
• no ip address: Remove the configured IP address from the interface.
• show startup-config: View the configuration in NVRAM (startup configuration file).
• show running-config: View the current configuration in RAM.
• copy running-config startup-config: Save the current configuration to the startup configuration file, so that it is used next time the router starts up.
• write: Save the current configuration to NVRAM (startup configuration file).
• erase startup-config: Clear the configuration stored in NVRAM, essentially clearing the startup configuration file.
• show ip interface brief: View the essential information of all interfaces.
• banner motd # [message] #: Configure the router or switch message-of-the-day (MOTD) banner.
• description [message]: Add a description to an interface.
• vlan database: Enter VLAN database mode.
• vlan [vlan number] [name]: Create a VLAN and assign a name to it.
• switchport access vlan [vlan number]: Assign a VLAN to an interface (access mode).
• interface vlan [vlan number]: Enter VLAN interface configuration mode.
• ip address [IP address]: Configure an IP address for a VLAN interface.
• vtp [service/client/transparent]: Configure the VTP (VLAN Trunking Protocol) mode for the switch.
• vtp domain [domain name]: Configure the VTP domain for the switch.
• vtp password [password]: Configure the VTP password for the switch.
• switchport mode trunk: Enable trunking mode on the interface.
• no vlan [vlan number]: Delete a VLAN.
• show spanning-tree vlan [vlan number]: View the spanning tree status for a specific VLAN.

Router Configuration Commands:

• ip route [non-direct network] [subnet mask] [next-hop address]: Configure static/default route.
• show ip route: View the routing table.
• show protocols: Display all passive routing protocols and which protocols are configured on each interface.
• show ip protocols: Display routing protocols configured on the router and provide information about timers used in the routing protocols.
• router rip: Activate the RIP (Routing Information Protocol).
• network [directly connected network]: Advertise a directly connected network in RIP.
• interface loopback 0: Activate the loopback interface.
• passive-interface [interface type] [interface number]: Configure an interface to be passive (used for protocols like RIP).
• debug ip [protocol]: Dynamically view routing update information for a specific protocol.
• undebug all: Disable all debugging output.
• router eigrp [AS number]: Activate the EIGRP (Enhanced Interior Gateway Routing Protocol).
• network [network] [subnet mask]: Advertise a directly connected network in EIGRP.
• show ip eigrp neighbors: View the EIGRP neighbor table.
• show ip eigrp topology: View the EIGRP topology table.
• show ip eigrp traffic: View the number of packets sent by EIGRP.
• router ospf [process ID]: Activate the OSPF (Open Shortest Path First) protocol.
• network [directly connected network] area [area number]: Advertise a directly connected network in OSPF.
• show ip ospf: Display OSPF process ID and Router ID.
• encapsulation [encapsulation format]: Change the encapsulation format of the interface.
• no ip domain-lookup: Disable domain name lookup on the router.
• ip routing: Enable routing functionality on a Layer 3 switch.
• show users: View online users on the switch.
• clear line [line number]: Clear a specific line on the switch.

Layer 3 Switch Configuration Commands:

1. Configure a group of Layer 2 ports:
   • configure terminal: Enter configuration mode.
   • interface range {port-range}: Enter range configuration mode to configure multiple ports.

2. Configure Layer 3 ports:
   • configure terminal: Enter configuration mode.
   • interface {fastethernet | gigabitethernet} interface-id | vlan vlan-id | port-channel port-channel-number: Enter port configuration mode for specific interfaces or VLANs.
   • no switchport: Convert the physical port to a Layer 3 port.
   • ip address [ip_address] [subnet_mask]: Configure IP address and subnet mask for the Layer 3 port.
   • no shutdown: Activate the port.

   Example:

   Switch(config)# interface gigabitethernet0/2
   Switch(config-if)# no switchport
   Switch(config-if)# ip address 192.20.135.21 255.255.255.0
   Switch(config-if)# no shutdown

3. Configure VLAN:
   • configure terminal: Enter configuration mode.
   • vlan [vlan-id]: Enter VLAN configuration mode, and specify a VLAN ID (new or existing).
   • name [vlan-name]: Optionally assign a name to the VLAN (default name is VLAN followed by the VLAN number).
   • mtu [mtu-size]: Optionally change the MTU (Maximum Transmission Unit) size.

   Example:

   Switch# configure terminal
   Switch(config)# vlan 20
   Switch(config-vlan)# name test20
   Switch(config-vlan)# end

   Alternatively:

   Switch# vlan database
   Switch(vlan)# vlan 20 name test20
   Switch(vlan)# exit

4. Assign ports to a VLAN:
   • configure terminal: Enter configuration mode.
   • interface [interface-id]: Enter the interface to which you want to assign the VLAN.
   • switchport mode access: Define the port as a Layer 2 access port.
   • switchport access vlan [vlan-id]: Assign the interface to a VLAN.

   Example:

   Switch# configure terminal
   Switch(config)# interface fastethernet0/1
   Switch(config-if)# switchport mode access
   Switch(config-if)# switchport access vlan 2
   Switch(config-if)# end

VLAN Trunk Configuration Commands

1. Enter Configuration Mode:
   • configure terminal: Enter global configuration mode.

2. Configure Trunk Port:
   • interface interface-id: Enter the port configuration mode (e.g., FastEthernet0/4).
   • switchport trunk encapsulation {isl | dot1q | negotiate}: Configure Trunk encapsulation type (ISL, 802.1Q, or negotiate).
   • switchport mode {dynamic {auto | desirable} | trunk}: Configure port trunk mode.
   • switchport access vlan vlan-id: Optionally, specify the default VLAN if the port is not in trunk mode.
   • switchport trunk native vlan vlan-id: Configure the Native VLAN for 802.1Q.

   Example:

   Switch(config)# interface fastethernet0/4
   Switch(config-if)# switchport mode trunk
   Switch(config-if)# switchport trunk encapsulation dot1q
   Switch(config-if)# end

3. Define Allowed VLANs on Trunk:
   • switchport trunk allowed vlan {add | all | except | remove} vlan-list: Configure the allowed VLANs on the trunk port.
   • no switchport trunk allowed vlan: Remove VLAN restrictions and allow all VLANs.

   Example:

   Switch(config)# interface fastethernet0/1
   Switch(config-if)# switchport trunk allowed vlan remove 2
   Switch(config-if)# end

4. Configure Native VLAN for 802.1Q:
   • switchport trunk native vlan vlan-id: Configure the Native VLAN for 802.1Q trunks.
   • no switchport trunk native vlan: Restore to the default Native VLAN.

   Example:

   Switch(config)# interface fastethernet0/2
   Switch(config-if)# switchport trunk native vlan 10
   Switch(config-if)# end

5. Configure Load Balancing based on Port Priorities:
   • spanning-tree vlan vlan-id port-priority priority: Configure port priority for specific VLANs.

   Example:

   Switch(config)# interface fastethernet0/1
   Switch(config-if)# spanning-tree vlan 8 port-priority 10
   Switch(config-if)# spanning-tree vlan 9 port-priority 10
   Switch(config-if)# end

6. Verify and Save Configuration:
   • show vlan: Verify VLAN configuration.
   • show running-config: View current configuration.
   • copy running-config startup-config: Save configuration.

Load Balancing by Configuring STP Path Cost

Trunk1 carries VLANs 8-10, Trunk2 carries VLANs 2-4

1. Enter Switch 1 configuration mode:

   configure terminal

2. Enter interface FastEthernet 0/1:

   interface fastethernet 0/1

3. Configure trunk encapsulation:

   switchport trunk encapsulation {isl | dot1q | negotiate}

4. Set the port mode to trunk (default is ISL encapsulation):

   switchport mode trunk

5. Exit the interface configuration mode:

   exit

6. Repeat steps 2-4 for interface FastEthernet 0/2:

   interface fastethernet 0/2

   switchport trunk encapsulation {isl | dot1q | negotiate}

   switchport mode trunk

   exit

7. Verify the running configuration:

   show running-config

8. Verify the VLANs learned by Switch 1:

   show vlan

9. Enter configuration mode again:

   configure terminal

10. Enter interface FastEthernet 0/1 again:

    interface fastethernet 0/1

11. Set the spanning-tree path cost for VLAN 2:

    spanning-tree vlan 2 cost 30

12. Set the spanning-tree path cost for VLAN 3:

    spanning-tree vlan 3 cost 30

13. Set the spanning-tree path cost for VLAN 4:

    spanning-tree vlan 4 cost 30

14. Exit configuration mode:

    end

15. Repeat steps 9-14 for interface FastEthernet 0/2 to configure spanning-tree path cost for VLANs 8, 9, and 10.
16. Save the configuration:

    copy running-config startup-config

Cisco Command Set – Routing Protocols and Troubleshooting

ip route Command

The ip route command is used to configure static routes:

Router(config)# ip route <network address or subnet> [subnet mask] <next hop IP address | exit address from local router> [administrative distance 0-255, default is 1]

Note: Static address configuration

ip default-network Command

The ip default-network command is used to define a default network, typically with a dynamic routing protocol:

Router(config)# ip default-network <destination network>

Note: Used with routing protocols to configure a default route based on one of the dynamic route numbers.

Router(config)# ip route 0.0.0.0 0.0.0.0 <next hop IP address | exit address from local router>

Note: Only used on the exit router when there is a single public IP address.

Interior Routing Protocols

Use the router and network commands to enable routing protocols:

Router(config)# router <routing protocol: rip | igrp | eigrp | ospf | is-is etc.> [AS number]

Router(config-router)# network <directly connected network that will use the routing protocol>

Router(config-router)# network <another directly connected network that will use the routing protocol>

Routing Information Protocol (RIP)

Router(config)# router rip

Router(config-router)# network <directly connected network with RIP>

Router# show ip protocols

Router# show ip route

Router# debug ip rip

Interior Gateway Routing Protocol (IGRP)

Router(config)# router igrp <AS number>

Router(config-router)# network <directly connected network with IGRP>

Router# show ip interface

Router# show ip protocols

Router# show ip route

Router# debug ip rip

ip route Command

The ip route command is used to configure static routes:

Router(config)# ip route <network address or subnet> [subnet mask] <next hop IP address | exit address from local router> [administrative distance 0-255, default is 1]

Note: Static address configuration

ip default-network Command

The ip default-network command is used to define a default network, typically with a dynamic routing protocol:

Router(config)# ip default-network <destination network>

Note: Used with routing protocols to configure a default route based on one of the dynamic route numbers.

Router(config)# ip route 0.0.0.0 0.0.0.0 <next hop IP address | exit address from local router>

Note: Only used on the exit router when there is a single public IP address.

Interior Routing Protocols

Use the router and network commands to enable routing protocols:

Router(config)# router <routing protocol: rip | igrp | eigrp | ospf | is-is etc.> [AS number]

Router(config-router)# network <directly connected network that will use the routing protocol>

Router(config-router)# network <another directly connected network that will use the routing protocol>

Routing Information Protocol (RIP)

Router(config)# router rip

Router(config-router)# network <directly connected network with RIP>

Router# show ip protocols

Router# show ip route

Router# debug ip rip

Interior Gateway Routing Protocol (IGRP)

Router(config)# router igrp <AS number>

Router(config-router)# network <directly connected network with IGRP>

Router# show ip interface

Router# show ip protocols

Router# show ip route

Router# debug ip rip