What is a CLI Stateful Firewall?

What is a CLI Stateful Firewall?


A CLI (command-line interface) stateful firewall is a type of firewall that monitors and filters packets based on the command line. This type of program uses TCP/IP for transport, which means it can be used to filter both incoming and outgoing traffic. The two most popular types are those that run as a daemon process in the background (daemon-based) or those that require user input at each packet (interactive).

A Command-Line Interface (CLI) is a means of interacting with a program where the user issues command by pressing keys to type in sentences, as opposed to using the mouse. A stateful firewall has two modes of operation: dynamic packet filtering and static packet filtering. Dynamic packet filters are able to provide stateful inspection of packets traversing between networks or systems.

What is a CLI Stateful Firewall and what does it do?

A CLI stateful firewall monitors the traffic to and from your computer. It looks for particular types of activity, such as peer-to-peer networking, BitTorrenting, and P2P downloading from pirate sites. If a certain type of traffic is detected, the firewall blocks that type of connection. As a result, these activities are prevented from taking up your bandwidth or slowing down your Internet connection.

While this feature is very useful, it can cause problems if you’re trying to access a site and your firewall drops the connection because of its settings. You may need to look through your firewall’s rules and find the one that relates to the site you need to access. Then, change it so it allows connections with that particular site.

How many types of CLI Stateful Firewall are there?

There are four types of CLI stateful firewalls:

– Packet Filtering: blocks incoming and outgoing packets

– Application Layer Inspection: scans the content of packets for malware or exploits

– Policy-Based Evaluation: analyzes TCP header, matches packets against firewall rule sets, and chooses which packet should be allowed based on rules matching

– Circuit Level Gateway: allows traffic to pass through a gateway to another network only when the connection is active

Why should you consider using a stateful firewall in your network?

A number of reasons to use a stateful firewall in your network:

– To create a more finely tuned filter for incoming and outgoing traffic

– To provide a way to observe and understand the behavior of attackers

– To provide security against denial of service attacks, which is an increasingly popular type of attack.

– To provide protection against machine misconfiguration (and therefore avoid the threat of an inside attacker)

– To account for transient connections, such as when a user accidentally leaves their laptop on overnight with open ports.

What are the benefits of using a CLI stateful firewall?

A CLI stateful firewall is beneficial for people because it keeps track of all traffic on the network. A CLI stateful firewall also reduces the chances of a Denial-of-Service attack. It also limits any TCP connection to be established with a specific IP address on the LAN.

This is beneficial for companies because they can determine what IP address can establish a TCP connection.  The administrator can designate what kind of ports are open on the firewall, making it easier to filter traffic.

What are the drawbacks of using a CLI stateful firewall?

CLI stateful firewalls are difficult to configure and maintain. The security device has a limited configuration and administrative interface and requires a lot of support from the vendor to fully utilize its capabilities. There is also a limited number of third-party applications that can be used to monitor CLI stateful firewalls. The data plane must be statically configured which makes it difficult for remote branches or locations without an IT staff member. The configuration and networking capabilities of CLI stateful firewalls are limited as traditional routers. The firewall has no ability to use routing protocols such as EIGRP, OSPF, or BGP to dynamically learn new routes all it can do is be configured statically on the device itself. Finally, adding a VPN connection into a CLI stateful firewall requires the same level of knowledge as configuring the device from scratch. There is no ability to use a single VPN connection and have it automatically added to all devices on the network.


A CLI stateful firewall is a type of network security system that analyzes the traffic and data packets to make sure they meet specific criteria. A CLI stateful firewall blocks any incoming or outgoing requests from computers on the outside that don’t match these criteria, preventing intrusion attempts by hackers and other malicious actors. With this kind of protection in place, you can rest assured your company information will be safe online. That said, there are some drawbacks: It requires more bandwidth than most firewalls because it needs to process all packets for inspection; also, if one packet is flagged as suspicious but doesn’t actually match up with what’s specified in the policy ruleset then it gets blocked even though it might not have been an actual threat – so be sure you have the bandwidth before deploying any type of stateful firewall.

Recent Posts