Showing posts from April, 2019

It’s the Middleman – Proxy Firewall

How many of you have applied proxy for one of your friends during the attendance call in the class? If I assume, it’s a yes from everyone, you will have no difficulty in understanding this one. Proxy is someone who is acting on your behalf and acting as the middleman. We take a more detailed example in some time to clearly understand this. A proxy firewall stands between a trusted and untrusted network and makes the connection, each way, on behalf of the source. When you as a user, will send a request to, say connect,, the request will go through the proxy firewall to check what request has been made. The proxy firewall will stop your connection, initiate a new connection on your behalf and wait for the incoming traffic. Surely, it finds that you have requested for a website which is quite known for leaking personal data, it stops the traffic and sends you a message that this website cannot be connected to. This is unlike the packet filtering firewall. Where

Which State are you in? I’m Stateful.

In continuation with our series on understanding the firewalls, the next type is the stateful firewall. This one remembers and keeps track of what packets went where until each particular connection is closed. To understand this one, we need to take an example. If you watch a little bit of crime drama, you will find that in most cases the neighbor knows everything. He is spying day and night on you and others in the neighborhood. He knows that the man on the left side of the road deals in weed and goes out of the house in the night, the construction guy who takes long breaks inside the garage, the milkman who smiles and pours extra milk looking at the handsome guy that lives next door and so on. Most of the well-known protocols have a sequence of connecting. For eg – If you consider the TCP protocol which is a connection-oriented protocol, it goes through three steps before a connection is established. This is commonly known as the 3-way handshake. If my system wants to c