Second, originally, I didn`t take into account return traffic, which can`t return through the ACL without additional configuration. I can think of very few situations where I want to reach one VLAN from another but I`m not interested in the answer. It seems that Cisco has even abandoned traditional ACLs in favor of contextual access controls (CABCs), which essentially turn stateless ACL behavior into stateful behavior. Are ACLs commonly used in all but the most extreme situations where ACLs are configured to completely isolate VLANs, or is it more common/preferable to use a router configuration on a key in conjunction with a stateful firewall? Maintenance seems to be much easier to manage this way. The term firewall is not so much a technical term as it is a marketing term or term. A firewall assumes an unprotected external network and a protected internal network. Early firewalls recorded transport log messages in temporary tables (in memory) so that connections could be monitored. Later, the firewalls performed a thorough packet inspection, which meant that the firewall was aware of the expected behavior of the different applications. Next, next-generation firewalls added application awareness and control, built-in intrusion prevention, and threat intelligence provided by the cloud. First, firewalls perform stateful scanning, while ACLs are only stateless. Stateful is a flow plot inspection, while Stateless (ACL) is a parcel inspection per package.
In other words, the « state » of the river is tracked and stored by the traditional firewall. In fact, firewalls can also include TCP SYN and SYN-ACC packets that ACLs cannot run on Layer 3 routers or switches. In addition to address/port matching and connection status management, many more advanced firewalls are able to use deep packet inspection to track application-level behavior. These are scenarios where stateless filters turn on and the things you should NEVER do on a stateful firewall. L3 ACLs are not the keystone of security, they are just another tool in the box. Nowadays, you need a NAC solution like Cisco ISE to secure the internal « borderless network ». However, I leave the firewalls on the perimeter. We also assume that we have been able to provide enough information to compare ACL-based firewall policies and zone-based firewall for your needs in an effective firewall requirement. Share your thoughts and experiences with us to get a practical understanding of the concept in question. Also share with us any other contributions that can help us broaden the horizons of our knowledge. Firewalls can be software or hardware.
Hardware firewalls are the preferred choice when it comes to large-scale deployments that require dedicated appliances to meet security requirements. Unlike firewalls, ACLs are features on routers and Layer 3 devices. In addition, ACLs (standard or advanced) can perform traffic control up to layer 4, i.e. Ports and protocols, while firewalls can reach up to layer 7 (application layer) of the OSI model. ACLs work with a set of rules that define how a packet is routed or blocked at the router`s interface. When used in firewalls, ACLs can control access to file systems or networks. Thus, the two types of ACLs are network ACLs and file system ACLs. I have found many answers to this question, none of which satisfies me for lack of details. Can someone explain in detail what a firewall is and what its purpose is, and what is an ACL and what is its purpose, and why are these two not the same? What are the differences in functionality, purpose, deployment, administration, and everything else? An access control list (ACL) contains rules for accessing a service or resource.
The beneficiary can be a user or a system, such as software. When an ACL is implemented on a router at the edge of the network, it acts as a firewall, blocks access from blocked addresses, and filters certain content. An ACL can also be placed for outbound traffic. ACLs can also be configured on switches to control internal network traffic. ACL rules can be sophisticated, combining source and destination so that a user can be prevented from accessing specific destinations on the network. All right. To perform 10GB inter-VLAN routing in a firewall, it would require a fairly expensive firewall – of course, large companies can bear this type of cost, but for me, it`s completely impossible to use anything other than an L3 switch in a much smaller environment. Of course, it`s heavier to implement rules in a switch, but the benefits clearly outweigh the costs. I set up my configuration in the same way – rules for inbound traffic on each IVR.
Works very well. With a terrible metaphor, think of your router as a 4×4 truck, while your firewall looks more like a Maserati. A router can perform stateless filtering near line rate without having to purchase additional hardware. A firewall requires a much larger processor/ASIC/memory to provide the same throughput. Before you can implement a zone-based firewall option, you must choose the different zones for which you must apply the option. The entire infrastructure is divided into different zones with different levels of security. A better approach in situations like this would be a hybrid setup. Route L3 between all ground data VLANs in a VRF. Stop all other VLANs in the Edge Firewall of this site. Choosing an ACL router to protect high-performance resources such as applications or servers may be a better option.
Although ACLs may not provide the level of security provided by a stateful firewall, they are optimal for endpoints on the network that need high speed and the necessary protection. Although a stateful firewall offers much better security, it can affect network performance. But an ACL is provided directly on the interface, and the router uses its hardware capabilities to process them, which makes them much faster and still offers a good level of security. The criteria for defining ACL rules can be the source, destination, a particular protocol, or other information. Firewalls* are stateful devices. They also transmit or block packets based on the data, but they « understand » the semantics of the data and can apply the semantics of the protocol based on the data included in the previous packets. For example, a firewall can check a TCP exchange and ensure that the acknowledgements match the data sent or that the flags are set correctly. You can implement both ACL-based CBAC firewall and zone-based firewall options at the same time. However, you cannot apply them to the same interface. Well, this should be the brief explanation of what zone firewalls are. The concept of zone firewall is a bit complicated and can be quite difficult to understand.
However, if you are new to them, it should be a good option to implement them. Well, configuring zone-based firewalls has its advantages and is quite easy to follow. CBAC has the following limitations: The internal router, located between the DMZ and the trusted zone, can be configured with more restrictive rules to protect the internal network. However, it`s a great place to choose a stateful firewall over an ACL. Why not use your router to block tons of unnecessary traffic that your firewall should never receive (like those annoying DNS/NTP/Memcache amplifications), deploy BCP38 to the next part of your network edge, and limit the required traffic (like ICMP/NTP/DNS) that should never exceed your firewall`s throughput? Why not try your traffic with and store it in a flow analyzer to get a better overview of what goes in and out of your network without the need for expensive syslog analysis solutions (money/time)? Or if you have two or more ISPs, are you preventing your network from being someone else`s means of transportation? What are the considerations for one over the other? I can imagine that if you don`t expect a high level of interVLAN routing, this is another voice for the router-on-a-stick/firewall route.