A proxy firewall filters at ...
A firewall and a proxy server sit between the network and the local computer to protect against network threats. The firewall and proxy server work together. The firewall operates at a lower level and can filter all types of IP packets while the proxy server processes traffic at the application layer and filters requests from an unknown client.
The proxy server can be thought of as part of the firewall. A firewall basically prevents unauthorized connections from accessing. On the other hand, a proxy server basically acts as an intermediary that establishes a connection between an external user and the public network.
comparison table
| Basis for comparison | Firewall | Proxy server |
|---|---|---|
| main | Monitors and filters incoming and outgoing traffic on the local network. | Establishes communication between an external client and a server. |
| filters | IP packets | Client connection requests. |
| Generated overhead | More | Less |
| Assumes | Network and transport layer data. | Application level data. |
Defining a firewall
The firewall creates a barrier through which traffic in the other direction must pass. It functions as a filter at the IP packet level and offers an effective method of protecting, monitoring, auditing the local network against external network security threats, IP spoofing, and routing attacks. It is an integrated network security solution that provides not only hardware but software security as well. A firewall is a collection of packet filters and proxy servers (application gateway).
A packet filter is used to forward and block incoming and outgoing packets according to information provided in the header of the network and transport layers, such as source and destination addresses, port numbers, protocol, and so on. On the other hand, a proxy server filters application layer data by examining the content of the message itself, the proxy server is discussed in more detail below.
The main strategies used by the firewall to control access and enforce security policy are service control, direction control, user control, and behavior control.
Service Control - Specifies which internet service should be accessed, inbound or outbound.
Direction Control - Determines which route must be taken for data to travel on the network.
User Control - Controls access to the service, according to which the user tries to access the service.
Behavior Monitoring - Determines the use of services.
Packet filter firewall and Application Proxy firewall
Defining a proxy server
A proxy server is also known as an application gateway because it controls traffic at the application layer. Despite examining raw packets, it filters data based on header fields, message size, and content. As mentioned above that the proxy is part of the firewall, a packet firewall alone would not be possible as it cannot distinguish between port numbers. A proxy server behaves like a proxy and makes decisions to control traffic flow specific to the application (using URLs).
When the proxy opens a request, it checks all content. If the request and its contents appear to be legitimate, the proxy server sends the request to the real server as if it were a client. Also, if the request is not a legitimate request, the proxy will immediately remove it and send an error message to the external user.
Another advantage of a proxy server is caching, when the server receives a request for a page, which it first checks to see if this page response is stored in the cache or not, if such a response is not saved, the proxy server sends a corresponding request to the server. So the proxy reduces traffic, loads the real server, and increases latency.
Key differences between firewall and proxy
A firewall is used to block traffic that could cause some damage to the system, it serves as a barrier to inbound and outbound traffic on the public network. On the other hand, a proxy server is a component of a firewall that allows communication between a client and a server, if the client is a legitimate user, and acts as a client and a server at the same time.
- The firewall filters IP packets. In contrast, a proxy server filters the requests it receives based on the content of its application layer.
- The overhead created in a firewall is greater compared to a proxy because the proxy uses caching and handles fewer aspects.
- The firewall uses network and transport layer data, while proxy processing also uses application layer data.
Conclusion
Firewall and proxy server works in integration. However, the proxy server is a component of the firewall that, when used in conjunction with the firewall, provides feasibility and greater efficiency.
