Table of contents

  1. 0. CCNA Exam Questions
  2. 7. Overview of Cisco Routers
    1. 7.3 Interfaces
  3. 8. Basic Router Management
    1. 8.1 Features of CLI (useful comamnds I guess)
      1. 8.1.1 Help System
      2. 8.1.2 Abbreviations
      3. 8.1.3 Editing Features
      4. 8.1.4 Command History
    2. 8.2 Obtaining General info as a router
    3. 8.3 Config Management (VERY IMPORTANT)
      1. Lab 1: Backuping configs to TFTP server
    4. 8.4 Configuring Password and Telnet Access
    5. 8.5 service password-encryption
  4. 9. Static Routing
    1. 9.1 Route entries for directly connected networks
      1. 9.1.1 Routes for directly connected networks
  5. Simulation 13

5th Lesson - CCNA Fast Track (May 27, 2025). We left off at page 80.

0. CCNA Exam Questions

    1. You need to save ram before clicking next in the CCNA exam via copy run start
    1. Need to know how to use vty to telnet and verify the connection + something else

7. Overview of Cisco Routers

7.3 Interfaces

Let’s conclude and compare teh serial and ethernet interfaces

  • Terminologies:
    • LAN = Local Area Network
    • WAN = Wide Area Network (e.g. Leased Line)
N/AEthernet Interfaces (e.g. f0/0, g0/0)Serial Interfaces (e.g. s0/0/0)
Typically used inLAN/ WANLAN only
L2 ProtocolEthernetHDLC/PPP (OutSyll!)
Config setupsee belowsee below
  • Configuration setup:
    • Ethernet:
      •   en
  config t
  int g0/0
  ip address 10.0.0.1 255.0.0.0
  no shut
  end
    • Serial: (treat is as normal routing port)
      •   en
  config t
  int s0/0/0
  ip address 10.0.0.1 255.0.0.0
  no shut
  end

8. Basic Router Management

8.1 Features of CLI (useful comamnds I guess)

8.1.1 Help System

  • help, help system can help you with commands instructions
  • show ? in user mode can tell you a list of commands to type

8.1.2 Abbreviations

  • show version can also be typed as sh version
  • config t = conf t, it works since there’s no other command than config when you type conf

8.1.3 Editing Features

  • ctrl + a = jump to start of the line in cli
  • ctrl + e = jump to end of the line in cli

8.1.4 Command History

  • You can call history buffer using the up arrow

8.2 Obtaining General info as a router

  • You can use sh ver to disaplay software and hardware infos
  • Primary RAM: 249856 byte
  • Secondary RAM: 12288 byte
  • Flash memory size is now 2256 Mb

8.3 Config Management (VERY IMPORTANT)

There are 2 diff locations in the rouer to store configs

running-configstartup-config
Stored in RAM, all commands are lost when router reloadsStored in NVRAM
Contect is dynamic, updated per config command enteredRouter boost up and load startup-config file to running config
Can be checked with sh running-configCan be checked with sh startup-config

  • To preserve the content in running-config copy run start & copy running-config startup-config

  • Step 1: Setting IP address
    en
config
hostname Router2
int g0/0
ip address 10.0.0.2 255.0.0.0
no shut
end
  • Step 2: sh run = shows configs are being run right now Router
  • Step 3: sh start. Oh, no configuration saved in startup-config
    startup-config is not present
  • Step 4: copy run start to copy the running-config from RAM to startup-config in NVRAM
    copy run start
Destination filename [startup-config]?
Building configuration...
[OK]
  • Step 5: sh start to check your new config copied over ti startup-config :D

Lab 1: Backuping configs to TFTP server

  • Topology:

  • Step 1: Sanity Check from router 1: ping 172.23.66.3.
    Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.23.66.3, timeout is 2 seconds:
!!!!
Sucess rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
  • Step 2: copy run tftp, you then punch in your address/ name of remote host
    Address or name of remote host []? 172.23.66.3
Destination filename [router1-confg]?
!!
1159 bytes copied in 1.097 secs (1057 bytes/sec)
  • You’ll then see in the tftp server

8.4 Configuring Password and Telnet Access

  • There are 4 types of password can be configured
    • Enable Password/ secret
      • Use: Preventing unauthroized access to Privileged Mode
      • Example: with password as sadmin
          en
  config t
  hostname Router1
  enable secret sadmin
  end
  disable
    • Console password
      • Use: Preventing CLI access through console port connection. line console 0/ line con 0 refers to interface console 0.
      • login means this password checking rule is actually implements
      • Example:
          config t
  line console 0
  password cadmin
  login
  end
    • VTY = Virtual Teletype (like remote access)
      • Use: Preventing CLI access to telnet connection
        • Configuring IP address on a router interface/ VLAN interface for a switch
        • Configuring password in Line config mode for telnet connection = setting VTY Password
      • Topology:
      • Example:
          config t
  int g0/0
  ip address 10.0.0.1 255.0.0.0
  no shut
  line vty 0 4
  password tadmin
  transport input telnet
  end
      • line vty 0 4 : entering line config mode for vty for remote access, we configure 5 vty lines (0-4 vty lines). Max 5 telnet sessions is allowed

      • transport input telnet : Configuring line vty 0 4 accept telnet connections

      • After this configuraiton, Router 2 can TCP/IP to Router 1
          config t
  int g0/0
  ip address 10.0.0.2 255.0.0.0
  no shut
  end


        When you telnet in Router 2 telnet 10.0.0.1, you’ll need password now

        Trying 10.0.0.1 ... Open

  User Access Verification

  Password:

    • 8.5 service password-encryption

      • sh run will tell you you have no service password-encryption
          show run
      • Any secret will be hashed but other passwords won’t
        • secret: auto encryption
        • passwords: manual encryption
      • To setup and enable service password… you do service password-encryption when your passwords are NOT encrypted on the run config
      •   config t
  service password-encryption
      • Sanity check with sh run again
      • Note: These encrypted passwords are NOT save, use cisco 7 password 7 website can easily decrypt this. Password should better to stored on AAA servers!

9. Static Routing

9.1 Route entries for directly connected networks

9.1.1 Routes for directly connected networks

  • Note: please reload your system and clear everything with reload
  • Suppose router has 2 interfaces (= 2 ports) with different IP address on different networks
    • IP 10.0.0.0/8 connected to g0/0 on Router 1 on IP 10.0.0.1/8
    • s0/0/0 on Router 1 on IP 192.168.1.1/24 connected to 192.168.1.0/24
  • Routing table of Route 1 auto includes routes for 10.0.0.0 and 192.168.1.0 ```bash Routing table of router 1 ———————————–

Network Destination Gateway Interface 10.0.0.0/8 directly connected g0/0 192.168.1.0/24 directly connected s0/0/0

- The topology: ![](../../../../../assets/images/ccna/lesson6/lesson6_dcn_1.jpg)
- The setup
    - Step 1: `no shut` meaning no ip is set
    ```bash
    en
    config t
    hostname Router1
    int g0/0
    no shut
    end
    ```
    - Step 2: `sh ip route`. Note the usable IP range is 10.0.0.1 ~ 10.255.255.254
    ```bash
    Codes: I - IGRP derived, R - RIP derived, O - OSPF derived
       C - connected, S - static, E - EGP derived, B - BGP derived
       * - candidate default route, IA - OSPF inter area route
       E1 - OSPF external type 1 route, E2 - OSPF external type 2 route

    Gateway of last resort is not set
        10.0.0.0/8 is variably subnetted, 2 subnet, 2 masks
    C   10.0.0.0/8 is directly connected, GigabitEthernet0/0
    L   10.0.0.1/8 is directly connected, GigabitEthernet0/0
    ```
    This route for the directly connected network (i.e. 10.0.0.1) on interface g0/0 is auto generated & found in routing table

    - Note:
        - If router goes downn, it resets and routing table is EMPTY even when IP address is assigned but interfaces are down
        - Showing a brief summary of all assigned IP and interface status via `shop ip interface brief`
        - status: representing L1 status, protocol: representing L2 status
        ```bash
        Interface           IP-Address      OK?     Method      Status                  Protocol
        GigabitEthernet0/0  unassigned      YES     NVRAM       up                      up
        GigabitEthernet0/1  unassigned      YES     NVRAM       adminstratively down    down
        GigabitEthernet0/2  unassigned      YES     NVRAM       adminstratively down    down
        GigabitEthernet0/2  unassigned      YES     NVRAM       adminstratively down    down
        ```
        - Note: 
            - `up up` = `no shutdown` is used to turn on ports and up up means a proper connection is detected
            - `adminstratively down    down`  = interface/ router is not broken, just down due to `shutdown` command

## 9.2 InterVLAN Routing (Router-on-a-strick & L3) examples 
- Single router designs with properly set up, routing can happen without extra configs
- Multilater or L3 Switch can route IP packets based on L3 info in IP packets

### 9.2.1 InterVLAN 1 -  Configuring Routing Using a Multi-layer Switch (via L3) 
- Topology: ![](../../../../../assets/images/ccna/lesson6/lesson6_ivlan_1.jpg)
    - Don't forget to set the correct IP
    - Step 1: The setup, `no switchport` will turn a port from L2 to L3
    ```bash
    en
    config t
    hostname Switch1
    ip routing
    int g1/1
    no switchport
    ip addr 10.0.0.1 255.0.0.0
    int g0/2
    no switchport
    ip addr 172.16.0.1 255.255.0.0
    ```
    - `ip routing` enabling L3 IP routing in multi-layer switch
    - Step 2: Perform sanity check with `show ip route`:
        - L represents the Host Route, can be disregarded
        ```bash
        Codes:  I - IGRP derived, R - RIP derived, O - OSPF derived
                C - connected, S - static, E - EGP derived, B - BGP derived
                * - candidate default route, IA - OSPF inter area route
                E1 - OSPF external type 1 route, E2 - OSPF external type 2 route

        Gateway of last resort is not set
            10.0.0.0/8 is variably subnetted, 2 subnet, 2 masks
        C   10.0.0.0/8 is directly connected, GigabitEthernet1/1
        L   10.0.0.1/32 is directly connected, GigabitEthernet1/1

            172.16.0.0/16 is variably subnetted, 2 subnet, 2 masks
        C   172.16.0.0/16 is directly connected, GigabitEthernet0/2
        L   172.16.0.1/32 is directly connected, GigabitEthernet0/2
        ```
    - Step 3: Configure Router 1
    - `ip route 0.0.0.0 0.0.0.0 10.0.0.1` configure the default gate of Router 1 to 10.0.0.1 (Will go into detail next time)
    ```bash
    en
    config t
    hostname Router1
    int g0/0
    ip address 10.0.0.100 255.0.0.0
    no shut
    exit
    ip route 0.0.0.0 0.0.0.0 10.0.0.1
    end
    ```

    - Step 4: Configure Router 2
    - 
    ```bash
    en
    config t
    hostname Router2
    int g0/2
    ip address 172.16.0.200 255.255.0.0
    no shut
    exit
    ip route 0.0.0.0 0.0.0.0 172.16.0.1
    end
    ```
    - Step 5: sanity check previlage mode
    - 
    ```bash
    ping 10.0.0.100
    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to 10.0.0.100, timeout is 2 seconds:
    !!!!!
    Success rate is 100% (5/5), round-trip min/avg/max = 3/4/6 ms
    ```

    - If fail, debug with `sh ip route` 

### 9.2.2 InterVLAN 2 - Configuring Routing Using a Multi-layer Switch (via L2, VLAN interface)
- Topology diagram: ![](../../../../../assets/images/ccna/lesson6/lesson6_ivlan_2.jpg)

- Benefit of this topology:
    - No single point of failure
    - no physical issue/ connections
    - interVLAN hard to go down

- Step 1: Setup Switch 1
- `switchport mode access` gurantees there will be NO Trunk Link
```bash
en
config t
hostname Switch1

vlan 2

int g1/1
switchport mode access
switchport access vlan 1

int g0/2
switchport mode access
switchport access vlan 2

exit
  • Step 2: Turn on InterVLAN routing
  • ip routing enable IP Routing L3 or Multi-layer switch ```bash ip routing int vlan 1 id address 10.0.0.1 255.0.0.0

no shut int vlan 2 ip address 172.16.0.1 255.255.0.0 no shut end

- Note: `int vlan 1` and `int vlan 2`. The above enale routing feature and configures IP addresses

- Step 3: Sanity check Switch with `sh ip route`
-    
```bash
Codes: I - IGRP derived, R - RIP derived, O - OSPF derived
    C - connected, S - static, E - EGP derived, B - BGP derived
    * - candidate default route, IA - OSPF inter area route
    E1 - OSPF external type 1 route, E2 - OSPF external type 2 route

    Gateway of last resort is not set
        10.0.0.0/8 is variably subnetted, 2 subnet, 2 masks
    C   10.0.0.0/8 is directly connected, GigabitEthernet1/1
    L   10.0.0.1/32 is directly connected, GigabitEthernet1/1

        172.16.0.0/16 is variably subnetted, 2 subnet, 2 masks
    C   172.16.0.0/16 is directly connected, GigabitEthernet0/2
    L   172.16.0.1/32 is directly connected, GigabitEthernet0/2
  • Step 4: setting up Router 1
    en
config t
hostname Router 1
int g0/0
ip address 10.0.0.100 255.0.0.0
no shut
exit
ip route 0.0.0.0 0.0.0.0 10.0.0.1
end
  • Step 5: setting up Router 2
    en
config t
hostname Router2
int g0/2
ip address 172.16.0.200 255.255.0.0
no shut
exit
ip route 0.0.0.0 0.0.0.0 172.16.0.1
  • Step 6: Sanity Check Router 2 with ping 10.0.0.1.
ping 10.0.0.100
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.0.0.100, timeout is 2 seconds:
!!!!!
Success rate is 100% (5/5), round-trip min/avg/max = 3/4/6 ms

Note: Lesson ended on page 124

Simulation 13

  • Topology diagram:
  • Further solution: