A crucial part of network security is the management of firewall rules throughout the network and across the devices. In order to develop network security, the establishment of firewall rules is important for the following reasons-
- Firewall rules help to determine whether to allow or block certain traffic.
- Firewall rules inspect control information to allow or block that one defines in the individual packets.
- In order to protect the network from unauthorized access and malicious programs, rules control the mechanism of the firewall.
Firewall rules: Inbound and outbound
Inbound rules help to determine whether to allow or block incoming traffics and protect the network from disallowed connections, malware, denial-of-service (DoS) attacks, etc. Conversely, outbound rules control outgoing traffics from the network. In order to determine traffic destination, traffic source, service, denial of the traffic, andallowance, there are several firewall rules.
Elements of Firewall Policy:
In order to have an effective firewall policy, one needs to document the rules throughout the network and across multiple devices. One also needs to clarify the purpose of the existence of the rule and their intentions in the firewall policy.
The documentation of the rules should specify the following things-
- The purposes of the rules,
- How the rules will affect the applications and services,
- The users and devices that will be affected by the rules,
- The implementation and expiration date of the rules,
- The name of the implementor of the rules.
A formal change procedure helps the firewall policy in managing the change requests. The essence of the firewall policy is to allow only identified services and specific traffic, the rest should be blocked. One should also establish explicit drop rules or clean-up rules at each security zone. As ‘Accept All’ can not block unauthorized traffic, thus a firewall policy should not consider this, and also it should understand the detailed information about the traffic through built-in reporting tools. Frequent review of the firewall policy can also help the devices to remain up-to-date and to reduce false positives. In this ever-changing environment, regular review of the rules can make your rules relevant to the time.
Misconfigured or overly permissive rules can result in several risks and it is difficult to quantify and identify the risks because of complicated network and the growth of firewall rule sets. If one does not understand the applications and functions of a firewall and the flow of traffic at a certain time that can result in major firewall policy risks. While managing the changes in your network, it is important to consider that your network is like the flux, and if proper changes are not made, it can cause several risks such as getting hacked, going offline, and blocking legitimate traffic. Therefore, when you are making firewall rules, you should consider the following things-
- Assessment of the policy’s risk in the firewall,
- Safeguarding of the optimized firewall rules,
- Administration of the firewall changes,
- Demonstration of regulatory and policy compliance.