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Cisco IOS Dev

This guide covers essential CLI and GUI operations for Cisco switches and OpenWrt routers, including VLANs, port status, wireless setup, and more.

📡 Cisco Switch CLI Commands

🔌 Show Port Status

show interfaces status
Displays summary of all switch ports including status, VLAN, duplex, speed, and type.

🔍 Detailed Interface Info

show interfaces [interface-id]
Replace [interface-id] with the port (e.g., GigabitEthernet1/0/1) for detailed stats.

🧪 Check Interface Errors

show interfaces counters errors

⚙️ Show Port Configuration

show running-config interface [interface-id]

🧭 Show VLAN Status

show vlan brief
Lists all VLANs, their status, and assigned ports.

show vlan
Provides detailed VLAN info.

show interfaces [interface-id] switchport
Shows VLAN membership for a specific port.

show interfaces trunk
Displays trunk ports and allowed VLANs.

🧾 Show Switch Model

show version
Includes model number, IOS version, uptime, and serial number.

show inventory
Lists hardware components and part numbers.

🧠 VLAN IP Address

show ip interface brief
Shows IP addresses assigned to VLAN interfaces (SVIs).

If you see: 

Vlan1                  unassigned      YES NVRAM  administratively down down
It means: - No IP assigned - Interface is shut down

To fix: 

configure terminal
interface vlan 1
ip address 192.168.1.2 255.255.255.0
no shutdown
end
write memory

🔁 Reboot the Switch

reload
Reboots the switch. Confirm when prompted.

To schedule: 

reload in 5

❌ Shutdown the Switch

Cisco switches cannot be shut down via CLI. You must physically disconnect power.

🧱 Cisco WS-C2960S-48FPS-L Capabilities

  • Layer 2 switch
  • Limited Layer 3 (static routing only)
  • ❌ No DHCP relay (IP helper-address)
  • ❌ No site-to-site VPN support

Use a Layer 3 switch or router for full routing and VPN features.

🌐 OpenWrt Wireless Setup

🛠️ CLI Configuration

Edit /etc/config/wireless: 

config wifi-iface
    option device 'radio0'
    option network 'lan'
    option mode 'ap'
    option ssid 'MyOpenWrtWiFi'
    option encryption 'psk2'
    option key 'mypassword'

For client mode: 

config wifi-iface
    option device 'radio0'
    option network 'wwan'
    option mode 'sta'
    option ssid 'YourSSID'
    option encryption 'psk2'
    option key 'YourPassword'

Edit /etc/config/network: 

config interface 'wwan'
    option proto 'dhcp'

Apply changes: 

wifi reload

🖥️ GUI Configuration (LuCI)

Set Up Access Point

  1. Go to Network → Wireless
  2. Click Edit next to radio
  3. Set:
  4. Mode: Access Point
  5. SSID: MyOpenWrtWiFi
  6. Network: lan
  7. Encryption: WPA2-PSK
  8. Key: mypassword
  9. Save & Apply

Connect to Another Network (Client Mode)

  1. Go to Network → Wireless
  2. Click Scan
  3. Click Join Network
  4. Enter password
  5. Assign to new network (e.g., wwan)
  6. Set firewall zone to wan
  7. Save & Apply

Verify under Status → Overview or use Network → Diagnostics.