it-knowledge/src/solutions/networking.md

# Network Solutions [🌐]

This section documents my solutions to networking scenarios, including network configuration, troubleshooting, and security.

## Scenario Tags

| Tag | Description |
|-----|-------------|
| [v1-S7] | Network Configuration - Practice Scenarios v1 |
| [v2-S7] | Network and Storage Troubleshooting - Practice Scenarios v2 |
| [v3-S7] | Network Services Configuration - Practice Scenarios v3 |

## Scenario: [v1-S7] Network Interface Configuration

### Original Problem
From Practice Scenarios v1, Scenario 7:
1. Configure static IPv4 address: 192.168.1.100/24
2. Configure static IPv6 address: 2001:db8:1234:5678::100/64
3. Set hostname to 'rhcsa.example.com'
4. Configure DNS resolution using /etc/resolv.conf
5. Implement network access restrictions using firewalld zones

### Environment
- OS Version: RHEL/Rocky Linux 8.x
- Initial State: DHCP-configured network interface
- Required Outcome: Properly configured static network settings with hostname and firewall zones

### Solution Steps
1. Check Current Network Configuration
   ```bash
   # Check network interfaces
   ip addr show
   
   # Check routing
   ip route show
   ```
   The first step is to identify the current network configuration to understand what needs to be changed.

2. Configure Static IPv4 and IPv6 Addresses
   ```bash
   # Configure static IPv4 address
   sudo nmcli connection modify eth0 ipv4.addresses 192.168.1.100/24 ipv4.method manual
   
   # Configure static IPv6 address
   sudo nmcli connection modify eth0 ipv6.addresses 2001:db8:1234:5678::100/64 ipv6.method manual
   
   # Set default gateways
   sudo nmcli connection modify eth0 ipv4.gateway 192.168.1.1
   sudo nmcli connection modify eth0 ipv6.gateway 2001:db8:1234:5678::1
   ```
   This configures the static IP addresses on the network interface.

3. Set Hostname
   ```bash
   # Set hostname
   sudo hostnamectl set-hostname rhcsa.example.com
   
   # Update /etc/hosts
   sudo echo "127.0.0.1 rhcsa.example.com rhcsa" >> /etc/hosts
   ```
   This sets the system hostname and updates the hosts file.

4. Configure DNS Resolution
   ```bash
   # Configure DNS servers
   sudo nmcli connection modify eth0 ipv4.dns "8.8.8.8 8.8.4.4"
   
   # Apply changes
   sudo nmcli connection up eth0
   ```
   This configures the DNS servers and applies all the network configuration changes.

5. Configure Firewall Zones
   ```bash
   # Create a new zone for restricted access
   sudo firewall-cmd --permanent --new-zone=restricted
   
   # Add services to the zone
   sudo firewall-cmd --permanent --zone=restricted --add-service=ssh
   sudo firewall-cmd --permanent --zone=restricted --add-service=http
   
   # Add source network to the zone
   sudo firewall-cmd --permanent --zone=restricted --add-source=192.168.1.0/24
   
   # Reload firewall
   sudo firewall-cmd --reload
   ```
   This sets up a new firewall zone that restricts access to only SSH and HTTP from the local network.

### Verification
```bash
# Verify IP configuration
ip addr show

# Verify hostname
hostname

# Verify DNS resolution
dig google.com

# Verify firewall zones
sudo firewall-cmd --list-all-zones
```

### Key Learnings
- Network configuration with NetworkManager
- IPv4 and IPv6
- Firewall zone management
- DNS configuration

## Skills Demonstrated
- Network Configuration
- DNS Management
- Network Troubleshooting
- Network Security

## Scenario: [v2-S7] Network and Storage Troubleshooting

### Original Problem
From Practice Scenarios v2, Scenario 7:
1. Diagnose and repair failed NFS mounts
2. Recover from a failed LVM configuration
3. Fix network connectivity issues
4. Restore correct SELinux contexts after file restoration
5. Configure autofs for user home directories
6. Set up network teaming for redundancy

### Environment
- OS Version: RHEL/Rocky Linux 8.x
- Initial State: System with various network and storage issues
- Required Outcome: Fully functional system with resolved issues and properly configured network

### Solution Steps
[To be filled when I complete this exercise]

## Scenario: [v3-S7] Network Services Configuration

### Original Problem
From Practice Scenarios v3, Scenario 7:
1. Configure network with:
   - Bonded interface with active-backup
   - VLAN configuration
   - Static routes
2. Set up DNS resolution with:
   - Multiple DNS servers
   - Search domains
   - Local host entries
3. Implement network security with:
   - TCP Wrappers
   - IPtables rules
   - Fail2ban configuration

### Environment
- OS Version: RHEL/Rocky Linux 8.x
- Initial State: Basic network configuration with single interface
- Required Outcome: Advanced network configuration with bonding, VLANs, and security features

### Solution Steps
[To be filled when I complete this exercise]