iti 18 April 2025

🔧 Setting Up a Proxy Server / DHCP Server with Firewall

Setting up a proxy server, DHCP server, and a firewall is essential for managing network traffic, assigning IP addresses automatically, and ensuring network security. This guide will walk you through setting up these components for a network.

🎯 What is a Proxy Server?

A proxy server is an intermediary server that sits between a client (e.g., a computer) and the destination server (e.g., a website). It forwards requests from clients to servers and then sends the server’s response back to the clients. Proxy servers are used for security, content filtering, caching, and anonymity.

Advantages of a Proxy Server:

  • Improved security by hiding client IP addresses.
  • Content filtering to block unwanted websites.
  • Faster browsing through cached content.
  • Access control and monitoring of user activity.

🎯 What is a DHCP Server?

A Dynamic Host Configuration Protocol (DHCP) server automatically assigns IP addresses to devices on a network. It eliminates the need for manual IP configuration and ensures that devices receive unique IP addresses, reducing IP address conflicts.

Advantages of DHCP:

  • Automates IP address allocation.
  • Reduces manual errors and administrative overhead.
  • Ensures efficient IP address management and reuse.

🎯 What is a Firewall?

A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between a trusted internal network and untrusted external networks, like the internet.

Advantages of Firewalls:

  • Prevent unauthorized access to the network.
  • Monitor and control traffic flow.
  • Protect sensitive data and prevent cyber-attacks.
  • Offer logging and reporting for network activities.

🎯 Requirements for Setting Up the Servers and Firewall

  • Server machine: A physical or virtual machine to host the servers and firewall.
  • Operating System: A suitable OS (e.g., Linux for advanced users, Windows Server for ease of use).
  • DHCP Server Software: Built-in DHCP server functionality in the OS or a dedicated software like ISC DHCP Server (Linux) or Windows DHCP Service.
  • Proxy Server Software: Tools like Squid Proxy, CCProxy (Windows), or a similar tool for proxy server functionality.
  • Firewall Software: Built-in firewall (Windows Firewall, iptables on Linux) or advanced security software like pfSense.
  • Network Devices: Routers, switches, or hubs for network connectivity.

🎯 Steps for Setting Up the Proxy Server / DHCP Server with Firewall

Step 1: Setting Up the Proxy Server

Here, we’ll walk through the steps for setting up Squid Proxy on a Linux system. You can follow similar steps for other proxy servers like CCProxy for Windows.

  • Install Squid Proxy Server using the following command:
  • After installation, configure the proxy by editing the Squid configuration file:
  • Modify the http_port directive to define the port on which the proxy server will listen (default is 3128).
  • Set access control rules using the acl and http_access directives to control who can access the proxy server.
  • Restart the Squid service to apply the changes:
  • Configure client devices to use the proxy server by entering the server's IP address and port in their network settings.

Step 2: Setting Up the DHCP Server

Now, let’s configure the DHCP server. Here’s how to do it on Linux using the ISC DHCP server.

  • Install the ISC DHCP server using the following command:
  • Configure the DHCP server by editing the DHCP configuration file:
  • Specify the network settings, such as the subnet and range of IP addresses to assign to clients:
  • Ensure the DHCP server listens on the correct network interface by modifying the INTERFACESv4 in the configuration file:
  • Start the DHCP service:
  • Verify that devices connected to the network automatically receive IP addresses by checking the status:

Step 3: Setting Up the Firewall

Firewalls are essential for network security. On Linux, we will use iptables to configure basic rules. On Windows, you can use the built-in Windows Firewall.

  • To enable and configure iptables on Linux, use the following commands:
  • These rules allow incoming HTTP (port 80) and HTTPS (port 443) traffic, while blocking other incoming traffic.
  • To make these rules persistent across reboots, save them using:
  • For Windows Firewall, go to Control Panel → Windows Firewall → Advanced settings and configure inbound and outbound rules for different ports and services.

🎯 Testing the Proxy Server, DHCP Server, and Firewall

  • For the proxy server, try accessing the internet from a client machine that has been configured to use the proxy. The request should pass through the proxy server.
  • For the DHCP server, ensure that clients are receiving IP addresses automatically within the configured range.
  • To test the firewall, try to access a blocked port or service. The connection should be denied based on the firewall rules you set.

🎯 Troubleshooting Tips

  • If the DHCP server is not assigning IP addresses, ensure that the server is running and check the DHCP log files for errors.
  • If the proxy server is not working, check the proxy settings on the client machine and ensure that the proxy service is running.
  • If the firewall is blocking legitimate traffic, check the firewall rules and ensure that the necessary ports are open.

🎯 Summary

Setting up a proxy server, DHCP server, and firewall is essential for efficient network management, security, and ensuring smooth communication within a network. With the steps outlined, you can easily configure these components to enhance your network’s functionality and security.