Proxies

Praveen Bangera,

While designing infrastructure solutions, Proxies are utilized in different ways.

– Forward Proxy [ Egress Proxy ]
– Reverse Proxy [ Ingress Proxy ]


Forward Proxy vs Reverse Proxy:


Key Differences
Proxy servers act as intermediaries between clients and servers, but their direction of service determines whether they are forward or reverse proxies.


Forward Proxy:


A Forward Proxy is a type of proxy server that sits between a client and a server, acting as an intermediary for requests from the client to the server. It’s called a “forward” proxy because it forwards requests from the client to the server.

Key Characteristics:

  1. Client-initiated: The client initiates a request to the Forward Proxy, which then forwards it to the server.
  2. Server-agnostic: The client doesn’t know the details of the server; it only knows the Forward Proxy’s address.
  3. Request forwarding: The Forward Proxy forwards the client’s request to the server, and then returns the server’s response to the client.
  4. Anonymity: The client’s IP address is hidden from the server, as the request appears to come from the Forward Proxy’s IP address.
  5. Caching: Forward Proxies can cache frequently accessed resources, reducing the load on the server and improving response times.


Here are some product examples of Forward Proxies:

  1. Squid: A popular open-source Forward Proxy caching server for web traffic.
  2. Apache HTTP Server with mod_proxy: A widely used web server that can be configured as a Forward Proxy.
  3. NGINX: A web server and reverse proxy server that can also function as a Forward Proxy.
  4. HAProxy: A high-performance load balancer and Forward Proxy server.
  5. F5 BIG-IP: A comprehensive application delivery controller (ADC) that includes Forward Proxy capabilities.
  6. Cisco Web Security Appliance (WSA): A security-focused Forward Proxy for web traffic.
  7. Blue Coat ProxySG: A secure web gateway that functions as a Forward Proxy.
  8. IBM DataPower Gateway: A purpose-built appliance that includes Forward Proxy capabilities (as mentioned earlier).
  9. Microsoft Forefront TMG (Threat Management Gateway): A discontinued but still used Forward Proxy server.
  10. Pulse Secure: A secure access solution that includes Forward Proxy capabilities.
  11. Glabal Protect (Prisma): A secure access solution that includes Forward Proxy capabilities.

These products can be used in various scenarios, such as:

  • Content filtering and caching
  • Load balancing and application delivery
  • Security and threat protection
  • Access control and authentication
  • Web acceleration and optimization

Note that some of these products may offer additional features beyond Forward Proxy capabilities.

Web Proxy vs SOCKS Proxy:

Key Differences
Both web proxies and SOCKS proxies act as intermediaries between clients and servers, but they differ in their protocol support, functionality, and use cases.

Web Proxy:

HTTP/HTTPS protocol support only: designed specifically for web traffic
Understands web requests: can interpret and modify HTTP headers, cookies, and content
Caching and content filtering: can cache frequently requested resources and filter out unwanted content
Typical use cases: anonymous browsing, content filtering, caching, and accessing geo-restricted websites.


SOCKS Proxy:

SOCKS proxy servers redirect traffic through them before passing it on to the intended destination. This is achieved by first establishing a TCP connection with the proxy server through the SOCKS protocol.
Data can then be sent from your computer to the proxy server, which then relays it to the recipient

Multi-protocol support: handles various protocols like HTTP, HTTPS, FTP, SMTP, and more
Does not interpret traffic: simply forwards packets without modifying or caching content
Better suited for non-web traffic: ideal for applications like email, FTP, and torrent clients
Typical use cases: anonymous torrenting, accessing geo-restricted content, and bypassing firewalls


Reverse Proxy:
Server-side proxy: sits between servers and the internet
Hides server IP addresses: protects servers from direct access, improving security
Load balancing: distributes incoming requests across multiple servers
SSL termination: handles SSL encryption and decryption, reducing server load
Caching and compression: improves performance and reduces bandwidth usage
Typical use cases: server protection, load balancing, content delivery networks (CDNs)

Reverse Proxy:

A Reverse Proxy is a server that sits between a server and a client, acting as an intermediary for requests from the client to the server. It’s called a “reverse” proxy because it reverses the typical proxy flow, where the proxy sits between the client and the internet.

Key Characteristics:

  1. Server-initiated: The server initiates the connection to the Reverse Proxy, which then forwards requests to the client.
  2. Client-agnostic: The server doesn’t know the details of the client; it only knows the Reverse Proxy’s address.
  3. Request forwarding: The Reverse Proxy forwards the client’s request to the server, and then returns the server’s response to the client.
  4. Server protection: The Reverse Proxy hides the server’s IP address and protects it from direct client access.
  5. Load balancing: Reverse Proxies can distribute client requests across multiple servers to improve responsiveness and availability.

Flow:

  1. Client sends request to Reverse Proxy
  2. Reverse Proxy forwards request to Server
  3. Server processes request and sends response to Reverse Proxy
  4. Reverse Proxy returns response to Client

Benefits:

  1. Security: Protects server from direct client access and attacks
  2. Scalability: Enables load balancing and server scaling
  3. Flexibility: Allows for server maintenance and updates without affecting clients
  4. Caching: Can cache frequently accessed resources to improve performance
  5. SSL termination: Can handle SSL encryption and decryption, reducing server load

Common Use Cases:

  1. Web servers: Protect and load balance web servers
  2. API gateways: Manage and secure API traffic
  3. Microservices: Enable communication between microservices and clients
  4. Cloud services: Provide a single entry point for cloud-based services

DataPower as a Reverse Proxy:

IBM DataPower can be configured as a Reverse Proxy to provide advanced security, scalability, and performance features, such as:

  • Security: Authentication, authorization, and encryption
  • Load balancing: Distribute client requests across multiple servers
  • Caching: Cache frequently accessed resources
  • SSL termination: Handle SSL encryption and decryption
  • Content routing: Route requests based on content type or URL

By using DataPower as a Reverse Proxy, organizations can protect their servers, improve scalability and performance, and provide a secure and flexible infrastructure for their applications.

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