Zone-Based Firewall – Very Strong Firewall

What is the Firewall?

Before we dive into what Zone-based Firewall is, we have to take a strong look at the Firewall. A firewall is a thin layer of protection between the host computer and the server. Whatever amount of data the server computer receives and the amount of data host gets access on the server gets decided by the Firewall. If the user made a rule on the Firewall blocking the access of the server computer to theirs, then the Firewall would block all the access of the server computer to the user’s computer, vice versa.

Why is Firewall important?

It is the rule that makes the firewall work for all devices that are connected to that system. We are living in an age where safety is one of the deepest concerns for any company starting out on the Internet. The Internet is the most profitable place if utilized well. That’s why you see so many businesses entering the Internet, which makes these companies one of the targets for hackers to hack in. If the companies don’t follow a strong defense system, it won’t be a month before they get hacked lost all the data in the process.

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Zone-Based Firewall

Zone provides a boundary to a group of interfaces that shares the same network & functions. It evaluates the upcoming traffic with policy restrictions before letting it pass to another system. These policies help make the network system safer for the user and reliable to use. This safe Zone is called zone-based Firewall. If one local system is connected to the same router, then applying the Zone-based policy will inspect every connection before sending the connection to the destined location.

It is one of the heaviest used software in the multiple tech companies, as they are one of the most targeted often by hackers who want to take sensitive information out of them. That is why multiple companies use the Zone-based Firewall to lower the chance of hackers getting into their system.
Zone-based Firewall is an upgraded version of a stateful firewall. If you have no idea what that is, then don’t worry. A stateful firewall record everything about the connection in a stateful database — information such as IP address, the destination address of the data packet, port number.

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What Does Zone-based Firewall Do?

Now that you know what Zone-based Firewall is, it’s time to dig a little deeper into what exactly it does in a computer and how having a zone-based Firewall improves the efficiency of a network and computer?

  1. Drop: When it comes to the traffic in the network system, the drop is the default in the network service. This service gets used by the “class class-default” that dismisses the inspect-type policy-map. You can also configure other class-maps to let go of unwanted traffic. Any amount of traffic that goes through drop gets silently dropped without sending any sort of message or notification.
  2. Pass: Pass is one of the functions of the Zone-based Firewall, which helps the traffic to move to one location to another. The traffic here only moves in one direction.
  3. Inspect: The inspect action provides state-based traffic control to the system. The router tracks and maintains all the TCP/ UDP traffic information. The inspect function of the Zone-based Firewall also provides application review and control for certain service procedures that might have some sensitive venerable traffic to them.

Rules Zone-based Firewall

Since you know everything about the Zone-based Firewall and the function, it carries in them to provide a much stronger sense of security to the connections that get sent to the computer. It is time to learn about the rules you need to know to apply the Zone-based Firewall without troubleshooting every five minutes.

  • First step that you have to configure a zone before assigning any sort of interface to it.
  • Remember that an interface can only be applied to a single zone.
  • All the traffic that gets sent or received inside of the zone is permitted.
  • Traffic is not allowed from one zone to another, if you want to make that happen then you have to set up a new rule to it.
  • Policies should be made for effecting control for the identification of traffic and the action that needs to be performed of the traffic. It can either be accepted, deny, and inspect.
  • After creating a rule you can apply to only one zone. Remember that the movement of traffic goes only in one direction. So, if you want this to be two way, then you need to create another zone pair.
  • One of the most important things you should know about the Zone-based Firewall is the movement of traffic. Traffic that is meant to the router is called the safe zone. There are different levels to a safe zone, which adds a bit more functionality to the device. Traffic that gets sent from the router is called coming from a safe Zone. Traffics that are going to the router is called going to a safe zone.

Naming Terms for the Zone-Based Firewall

Although you are allowed to write down any name you desire on the zones, there are preferable names that do the job properly. These names are inside, outside, and DMZ.

  • Inside – This is for the private network, where one interface is connected to two PCs.
  • Outside – This is for the public network, where one interface is connected to only one public Internet.
  • DMZ – This is for the servers, where one interface is connected to two servers.

zone security PRIVATE
zone security PUBLIC
zone security DMZ
interface fastethernet 2/0
zone-member security PRIVATE
interface fastethernet 2/1
zone-member security DMZ
interface serial 1/0
zone-member security PUBLIC

Actions of Zone-Based Firewall

Now that you know the naming terms of the Zone-based Firewall. The next step is to learn what type of action they will provide.

  • Inspect – This is where the inspection of the data will get performed, where it will create a new entry in the stateful database. It will record the information on the protocols. So, it can learn about the new policies that have been made to the protocol.
  • Drop – if, in a case, the incoming traffic doesn’t match the policies. Then it will get dropped. If the traffic wants to continue, then it must be compatible with the newer policies.
  • Pass – If everything runs well, then traffic will get passed through the system. This is where the traffic will go through one zone from another, but no session would be maintained.

Creating Zones

Now that you fully know everything about the zone system, you are ready to set it up in your system. While it may not be easy to set the whole thing up but it won’t be that difficult either.

Create zones

Sound’s simple, in a way it is. All you have to do is create logical zones. After you are done creating zones. Then proceed to follow the next step.

Interface assignment

After the creation of a logical zone comes the addition of an interface to it. Remember that you are not allowed to sent traffic from one zone to another because the rules haven’t set yet for the transaction.

Create class-map

Once you are successfully created a zone and added an interface to it. The next step is to create a class map. This will help you find various information’s regarding the traffic. Some of the things you will get to know with class-map are the type of traffic, the address of the traffic (ICMP). So you can select the policy that suits the most for that traffic.

Create policy-map and allocate class-map to the policy-map

A class-map will help you find out what kind of traffic it is. With a policy map, you will know what type of policy or actions should be taken for the traffic.

  • Inspect: As the title suggests, this is where the inspection will get performed, any traffic from outside the network will get inspected for various details. The traffic from inside the network will not get inspected, as they would be more trusted.
  • Drop: If the traffic doesn’t match the policy, then the traffic will consider unwanted or unnecessary, and the traffic will get dropped afterward.
  • Pass: Like you, the traffic in a zone-based firewall will move from one zone to another. Pass section will perform the action, but it will not create a session state for traffic it receives. If you want the traffic to follow a two rule, then a new policy should get written to carry the objective.

Configure a zone-pair

Then it is up to you what kind of policy you want to apply to the zones. Or if you have zone pair (Which consists of multiple zones). The policy will decide what kind of action they will carry in which direction to move the traffic.

Conclusion on the Zone-Based Firewall

If you have multiple networks set up, then going for a Zone-based firewall system is one of the essential things to install in your working area. As it makes things much easier and safer, as all of the things will get included in a zone. You would be allowed to set up as many policies as possible to suit the environment that you want to set over the system you have. You can find the true balance between safety and an easier flow style. Grouping a lot of computers and using the firewall service without selecting the systems in the group one by one can save you time and money.



Ten years of experience in information and computer technology. Passionate about electronic devices, smartphones, computers, and modern technology.