What Is a Proxy Server Firewall?

What Is a Proxy Server Firewall?

A firewall is a network security system. It is used to monitor and filter network traffic.

Traditional firewalls control the flow of traffic within the network. It is not built to decrypt or inspect application protocol traffic.

A proxy firewall addresses this gap. It works at the application layer to secure the network.

In this article, learn all about proxy firewalls and their benefits.

What is Proxy Server Firewall?

What is Proxy Server Firewall

A proxy firewall is an advanced firewall security system. It operates on OSI (Open Systems Interconnection) Layers 3, 4, 5, and 7.

The OSI Model is a conceptual framework used to describe the functions of a networking system.

OSI Layers
Layer 7 Application
Layer 6 Presentation
Layer 5 Session
Layer 4 Transport
Layer 3 Network
Layer 2 Data Link
Layer 1 Physical

The proxy firewall acts as an intermediary between two systems. It protects the network by filtering traffic at the application layer.

A proxy firewall is also be called a gateway or application firewall.

Proxy means to serve as a substitute. A proxy firewall substitutes for the client that is sending the request.

Proxy firewalls monitor network traffic for core internet protocols. At the application layer, there are several protocols such as:

  • Domain Name System (DNS)
  • FTP
  • HTTP
  • Internet Control Message Protocol (ICMP)
  • Simple Mail Transfer Protocol (SMTP).

internet protocols

Proxy firewalls create and run processes that mirror a service as it runs on the end host. For example, the FTP Proxy Server mirrors the working of the FTP service.

Key features of a Proxy Firewall

  • Cache webpages to reduce bandwidth demands
  • Filters - caches, logs, and requests to secure network
  • Protect against network intrusion
  • Enforce security policies
  • Inspect application layer traffic
  • Prevent unauthorized users’ access on a network

How does Proxy Firewall Work?

Working of Proxy Server Firewall

Proxy firewalls secure connection between the internal network and the public internet.

The internal network must first interact with the proxy gateway to access the internet. A proxy server firewall acts as a gateway. It processes requests to initiate its response.

The proxy transfers data from the internal network to the internet. It receives information from the database and delivers it to the internal network.

When an external system sends in a request, the proxy firewall evaluates it. The request is processed following a set of security rules.

The proxy firewall decides whether to allow the connection request or to block it. In case the request is validated, the external network only has a connection to the proxy.

A proxy firewall has its own Internet Protocol (IP) address. The external network connection will not receive data packets from the client network. Instead, it receives it through proxies.

This process strengthens your network’s security.

Pros of Proxy Server Firewall

Advantages of Proxy Server Firewall

1. Security

Proxy firewalls provide enhanced security by working at the application layer. It verifies connection requests on a private network.

The benefit is it validates the user requesting the connection instead of the device.

Proxy firewalls monitor and filter all application data. It prevents a spoofing attack and detects DDoS attacks.

2. Logging Capabilities

Logs contain detailed reports on user activities.

Proxy firewalls have extensive logging capabilities. It examines the entire network packet rather than just the destination address and port number.

You can monitor the actual data that the user is sending across a connection.

3. Assessing Threats

Threat assessment is a process to identify and manage a potential threat. It lets you evaluate events that can affect network operations.

A proxy firewall enables you to assess threats at the application level. It uses deep packet inspection (DPI) and proxy based architecture.

You can analyze application traffic and discover advanced threats. Also, check the validity of network traffic.

4. Granular Access Control

Proxy firewalls give administrators more control over network traffic. You can configure the network for individual users and groups.

Determine the permission by which a user can securely access a resource. Also, control what functions individuals can perform.

5. User Anonymity

A proxy firewall allows users to hide the origins of their network. It protects a network by masking its IP address.

A proxy firewall forwards requests from its own IP.
This way, hackers do not get access to your network’s location from information packets. It is used to bypass geo-blocking on the internet.

Cons of Proxy Server Firewall

Disadvantages of Proxy Server Firewall

1. Compatibility

A proxy firewall is not compatible with all network protocols. This limits the applications that the network can support and secure.

Proxy agents are required to be developed for each new application. It is used to filter or route a network protocol to pass through the firewall.

2. Slow Performance

Due to heavy traffic, the overhead in setting up proxy firewalls increases. It may take more time to validate requests. This leads to slower performance.

You can balance it by using high-end servers to run your proxy.

3. Configurations

A proxy firewall must be set up in a way that no ports are left exposed. You need to ensure overall encryption. As a result, it can be difficult to configure.


Consider the following factors to decide which firewall to choose:

  • The size of the organization
  • The resources are available
  • The level of protection required

You can consider investing in a proxy firewall if it matches your security needs. Learn more about cloud security from the CloudPanel blog.

Shraddha S.
Shraddha S.
Technical Writer

With a master in Computer Science, Shraddha Singh has a lot of thoughts about Technology and the Cloud Services Industry. An Indian native and a professional Technical writer, she gets her management skills from IIT-B.

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