based on connections and not on single packets). Keeping states has the advantage that you can make more strict rules (i.e. A proxy firewall, also known as an application firewall or a gateway firewall, limits the applications that a network can support, which increases security levels but can affect functionality and speed.
Thirdly, is it okay to use stateful packet filter instead of packet filter?Ī stateful packet filter is still a packet filter so you can use it. Secondly,Isn't application proxy safer than packet filter considering proxy can filter bad data like virus? While a packet filter is much faster than an application proxy it is of no use if you actually need application level inspection.īut a packet filter has its use too as a way to separate networks or as the first line of defense like against DOS attacks.
The only criterion to decide if you use a packet filter or an application proxy should be the security requirements and not the performance. For example, if we install a web proxy based Firewall than it will only allow HTTP Protocol Data. See also the OSI model: a packet filter is at layer 4 while an application level gateway is at layer 7.įirstly,Why is a packet filter is enough in a situation where traffic is busy? Application level gateway would work only for the protocols which is configured. An application level gateway instead understand the protocol and can thus scan the body of a HTTP response for malware. This mean with a packet filter you are not able to filter web traffic for malware since it has no understanding of the applications protocols of the web (i.e. A packet filter is a firewall at the packet level. An application proxy (or more commonly called application level gateway) is a firewall at the application level.
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