Bob Explores Advanced Networking on AlmaLinux

His manager wanted a server that could handle VLANs, bridging, and advanced network configurations.
by İbrahim Korucuoğlu ( @siberoloji) |
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  4 minute read  

Bob Explores Advanced Networking on AlmaLinux

With his file-sharing setup complete, Bob turned his focus to advanced networking. His manager wanted a server that could handle VLANs (Virtual Local Area Networks), bridging, and advanced network configurations. Bob was eager to learn how to manage and optimize network traffic on AlmaLinux.

“Networking is the backbone of any system—I’m ready to become the backbone specialist!” Bob said, diving into advanced networking.

Chapter Outline: “Bob Explores Advanced Networking”

  1. Introduction: Why Advanced Networking?

    • The importance of VLANs, bridging, and advanced configurations.
    • Tools available on AlmaLinux.

  2. Setting Up VLANs

    • Understanding VLANs and their use cases.
    • Configuring VLANs on AlmaLinux.

  3. Configuring Network Bridges

    • What is a network bridge?
    • Setting up a bridge for virtualization.

  4. Using nmcli for Advanced Network Management

    • Configuring connections with nmcli.
    • Creating profiles for different network setups.

  5. Testing and Monitoring Network Configurations

    • Using tcpdump and ping for testing.
    • Monitoring with nload and iftop.

  6. Conclusion: Bob Reflects on Networking Mastery

Part 1: Introduction: Why Advanced Networking?

Bob learned that advanced networking concepts like VLANs and bridging are critical for efficient network segmentation, traffic control, and virtualization.

Key Concepts

  • VLANs: Separate a physical network into multiple logical networks for better security and performance.
  • Bridges: Connect multiple network interfaces to allow traffic to flow between them, often used in virtualized environments.

“Understanding VLANs and bridges will level up my networking skills!” Bob thought.

Part 2: Setting Up VLANs

Step 1: Installing Required Tools

  • Ensure the NetworkManager and vconfig tools are installed:

    sudo dnf install -y NetworkManager

Step 2: Configuring a VLAN Interface

Bob wanted to create VLAN ID 100 on the Ethernet interface enp0s3.

  • Create the VLAN configuration file:

    sudo nano /etc/sysconfig/network-scripts/ifcfg-enp0s3.100

  • Add the following content:

    DEVICE=enp0s3.100
BOOTPROTO=none
ONBOOT=yes
VLAN=yes
IPADDR=192.168.100.1
PREFIX=24

  • Restart the network:

    sudo nmcli connection reload
sudo systemctl restart NetworkManager

  • Verify the VLAN interface:

    ip -d link show enp0s3.100

Step 3: Testing VLAN Connectivity

Bob ensured the VLAN was working by pinging another device on the same VLAN:

ping 192.168.100.2

“VLAN configured—network traffic stays clean and organized!” Bob said.

Part 3: Configuring Network Bridges

Step 1: Creating a Bridge

Bob needed a bridge named br0 for connecting virtual machines.

  • Create the bridge configuration file:

    sudo nano /etc/sysconfig/network-scripts/ifcfg-br0

  • Add the following content:

    DEVICE=br0
TYPE=Bridge
BOOTPROTO=dhcp
ONBOOT=yes

Step 2: Adding an Interface to the Bridge

  • Edit the configuration file for the interface (enp0s3):

    sudo nano /etc/sysconfig/network-scripts/ifcfg-enp0s3

  • Modify it to join the bridge:

    DEVICE=enp0s3
BOOTPROTO=none
ONBOOT=yes
BRIDGE=br0

Step 3: Restarting the Network

Bob restarted the network to apply the changes:

sudo systemctl restart NetworkManager

Step 4: Verifying the Bridge

  • Check the bridge:

    brctl show

  • Verify the IP address:

    ip addr show br0

“With the bridge configured, my virtual machines can now talk to the external network!” Bob said.

Part 4: Using nmcli for Advanced Network Management

Bob discovered that nmcli simplifies network configuration and allows scripting for repeatable setups.

Step 1: Listing Available Connections

  • View active and available connections:

    nmcli connection show

Step 2: Creating a Static IP Configuration

Bob created a static IP profile for a server interface:

  • Add a new connection:

    nmcli connection add con-name static-ip ifname enp0s3 type ethernet ip4 192.168.1.100/24 gw4 192.168.1.1

  • Activate the connection:

    nmcli connection up static-ip

Step 3: Viewing Connection Details

  • Show detailed information about a connection:

    nmcli connection show static-ip

“nmcli is my new go-to tool for network automation!” Bob said.

Part 5: Testing and Monitoring Network Configurations

Step 1: Using tcpdump to Capture Packets

  • Install tcpdump:

    sudo dnf install -y tcpdump

  • Capture packets on a specific interface:

    sudo tcpdump -i enp0s3

Step 2: Monitoring Traffic with nload

  • Install nload for real-time traffic monitoring:

    sudo dnf install -y nload

  • Monitor traffic:

    nload

Step 3: Checking Bandwidth with iftop

  • Install iftop:

    sudo dnf install -y iftop

  • View bandwidth usage:

    sudo iftop -i enp0s3

“With these tools, I can monitor and troubleshoot network traffic like a pro!” Bob said.

Conclusion: Bob Reflects on Networking Mastery

Bob successfully configured VLANs, bridges, and advanced network setups, enabling seamless connectivity and traffic management. With tools like nmcli, tcpdump, and iftop, he felt confident diagnosing and optimizing his network.

Next, Bob plans to explore Linux Performance Monitoring and Tuning on AlmaLinux.


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