I will first make an introduction to zbf and then i will demonstrate how to configure it. The idea behind zbf is that we dont assign accesslists to interfaces but we will create different zones. Jul 07, 2015 in this article, we will consider the operation of zone based policy firewall zbf configured on a cisco ios router that is also doing network address translation nat. Mar 14, 20 admittedly, the zone based firewall is something that ive never actually implemented. The vulnerability is due to a logic flaw in a corner case scenario. The basic firewall wizard provides simple inside and outside zones policy while the advanced firewall wizard provides more flexibility including dmz services. Traffic between two interfaces in the same zone is allowed by default. Nov 05, 2012 in this post i will talk about cisco zone based firewall zbf which is a new approach to configure access control in the ios firewall. Cisco 2911 zone based firewall guest internet access. We also provides firewall web filter policy configuration services in india such as. Understanding zone based firewalls posted on march 18, 2011 march 5, 2011 by ryan earlier we talked about using cbac see the post understanding cbac the classic firewall and we mention some information about zone based firewalls but not nearly enough. Firewalls, tunnels, and network intrusion detection. Jan 16, 2010 hello and welcome to zonebased policy firewall video on demand session. Implementing a cisco ios zone based firewall catalyst switch.
Controlling intrazone traffic this post is intended to explain basic concepts pertaining to intrazone traffic within a cisco zonebased policy firewal zfw environment. The router blocks all traffic unless explicitly allowed. Deploying zonebased firewalls digital short cut ivan pepelnjak isbn. Zonebased firewallpart 1 of 2basic configuration youtube. This means that access lists firewall rules are applied to zones and not interfaces this is similar to ciscos zonebased firewall supported by ios routers. Zone based firewall configuration example and show commands. Zonebased policy firewall, cisco ios xe release 3s iv. A network firewall is similar to firewalls in building construction, because in both cases they are. Jan 29, 2014 when interface is a member of a security zone, all transit traffic to a different zone is dropped by default. The general premise to zbf is to put a routers interfaces into zones and then secure those zones one from another.
Cisco ios router can be made firewall through two methods. To determine whether a device is configured with zone based firewall, log into the device and issue the show zone security cli command. Jan 25, 2012 the default operation of the cisco zone based policy firewall zfw is to allow traffic to an from the router interfaces, irrespectively of zone pair security settings. The zone based firewall zbfw is the successor of classic ios firewall or cbac contextbased access control. Ive set up the 2911 with two zones, inside and outside, hoping to add the tunnel0 interface to the inside zone. With a zonebased firewall, the default is to block all traffic unless explicitly allowed. Dec 10, 2018 cscun94946 ios vulnerability in zone based firewall vs cisco 2960x switches both devices are running with latest image but still showing vulnerable.
In particular we are going to briefly present the firewall evolution from their beginning until today and under of which conditions we arrived on zone based firewalls. The zonebased firewall first appeared in the cisco ios version 12. Turning cisco router into a firewall with zone based firewall, dhcp snooping, and site to site vpn duration. The last task is to create zone pairs for the outbound and inbound. Zone based firewall, pptp passthrough i am seeing many people migrating from cisco cbac to zone based firewall zbf on 800 3900 series isr devices being used as internet edge firewalls due to the greater flexibility, and better interoperability with policy routing. Zone based firewall configuration example including show commands this blog post will take you through configuring the cisco zbf with show commands. To create three zones, inside, outside and dmz, follow these configuration steps. We have seen that ccp provides two firewall configuration wizards. To illustrate the different examples in this post i will use the following. Zonebased firewall concepts ccie notes networkology. Zone based policy firewall, cisco ios xe release 3s americas headquarters cisco systems, inc. If there is a need to modify this behavior, a systemdefined zone, whose reserved name is self, must come into the scene. Cisco zonebased firewall drops eigrp solutions experts. Nov 16, 2010 converting cbac to zone based policy firewall.
Palo alto firewalls security zones tap zone, virtual wire. Packet tracer configuring a zonebased policy firewall zpf. May 04, 2010 from design to implementation in under 10 minutes. The document claims that the performance of tcp session inspection was significantly increased in 12.
Outoforder packet processing support in the zonebased firewall application 14. In a configuration where an explicit policy is configured for the self zone to go out of its zone and for the traffic moving between the in zone and out zone, if any intermittent icmp responses are generated, then the zone based firewall looks for a explicit permit rule for the icmp in the self zone to go out of its zone. Jan 08, 2017 how does a zone based firewall implementation handle traffic between interfaces in the same zone. Lisa covers firewall technologies, diving into the concept of a firewall, firewall security contexts, and how to do a basic firewall configuration. Config using the block of public ips from centurylink. The pros and cons listed are just the pros and cons of the specific implementation not the general concept. Zonebased firewall zbf and network address translation nat. Cannot apply acls between security zone or zonepairs. May 18, 2012 in this 60 minute presentation from, cisco learning network vip instructor anthony sequeira walks you through the basic configuration of the zone based firewall.
Traffic that is desired to or sourced from the self zone is denied by default c. The purpose of this paper is to provide an overview of zone based firewalls. Feb 16, 2011 cisco firewall 2951 zone based firewall feb 16, 2011. Traffic between interfaces in the same zone is always. Find answers to cisco 2911 zone based firewall guest internet access from the expert community at experts exchange. Appendix b ipsec, vpn, and firewall concepts overview. Zonebased firewalls are a type of localized data policy that allows stateful inspection of tcp, udp, and icmp data traffic flows. You can assign an interface to more than one interface. However, ios zonebased firewall configuration above you see 3 routers. In this lab guide i will be showing you how to configure a cisco zone based firewall zbf using the following requirements.
A vulnerability in the zone based firewall feature of cisco ios and cisco ios xe software could allow an unauthenticated, remote attacker to pass traffic that should otherwise have been dropped based on the configuration. Zone based firewalls takes the thinking in zones approach to ict security to a practical level. My name is piotr matusiak and i work for micronics training as a technical instructor. Service policies are applied to zone pairs zonepair security t2i source trusted destination internet. The zonebased firewall cannot interoperate with waas and wccp, when wccp is configured with layer 2 redirect method. Basically, i want zone based firewall to be implemented in an example network and to be configu. Traffic flows that originate in a given zone are allowed to proceed to another zone based on the policy between the two zones.
I have a cisco 2911 router set up as a dmvpn hub in a hubspoke scenario using zone based firewalls and eigrp on the hub and spokes. In this graphic, we see a logical drawing of a network and some common zones. Cisco router cbac and zone based firewall setup petenetlive. Jun 21, 2008 the zone based firewall performance post has generated a few interesting comments. Prior to ipv6 support, the firewall supported only the inspection of ipv4 packets. She also compares different types of firewalls including stateless, stateful, and application firewalls. The firewall only supports generic routing encapsulation gre redirection. An attacker could exploit this vulnerability by sending traffic that would have been dropped by the policy. Introduction to firewalls firewall basics traditionally, a firewall is defined as any device or software used to filter or control the flow of traffic. Verify network connectivity prior to configuring the zonebased policy firewall. The zone must be configured before a can be assigned. Traffic is implicitly denied by default between interfaces the same zone.
Googling youll likely find all sorts of marketing in reference to products named zone based firewall or configuration guides for vendorspecific implementations e. The zone based firewall feature of ios aims to make using the router as a firewall slightly easier than it had been with the normal ios accesslists. Firewalls, tunnels, and network intrusion detection 1 firewalls a firewall is an integrated collection of security measures designed to prevent unauthorized electronic access to a networked computer system. It is not necessary that all traffic flowing to or from an interface be inspected. With ipv6 support, the zonebased policy firewall supports the inspection of ipv6 packets. Only layer 4 protocols, internet control messaging protocol icmp, tcp, and udp packets are subject to ipv6 packet inspection. Configure and implement a zone based firewall in a network with applications using cisco packet tracer. Cisco ios and cisco ios xe software zonebased firewall.
Mar 18, 2011 understanding zone based firewalls posted on march 18, 2011 march 5, 2011 by ryan earlier we talked about using cbac see the post understanding cbac the classic firewall and we mention some information about zone based firewalls but not nearly enough. Configuring a zone based firewall in cisco packet tracer. The zonebased firewall does not support when layer 2 redirect is configured as a redirection method in waas. Cisco ios software ips and zone based firewall vulnerabilities. Zone based firewall is the most advanced method of a stateful firewall that is available on cisco ios routers. William chu and an anonymous reader posted links to a cisco zbfw performance document. Turning cisco router into a firewall with zonebased firewall, dhcp snooping, and site to site vpn.
Aside from each zone assigned to an interface there is also a self zone which can be used to control traffic allowed to and from the router. Interface cannot be a part of a zone and a legacy inspect policy at the same time. Interfaces are assigned to zones, and inspection policy is applied to traffic moving between the zones. A zone pair is a pairing of two zones and a direction.
Zonebased policy firewalls examine the source and destination zones from the ingress and egress interfaces for a firewall policy. Converting cbac to zonebased policy firewall itsecworks. In this 60 minute presentation from, cisco learning network vip instructor anthony sequeira walks you through the basic configuration of the zonebased firewall. Palo alto networks nextgeneration firewalls rely on the concept of security zones in order to apply security policies. Vpn concepts b6 using monitoring center for performance 2. If the output shows a member interface under a zone name, then the device is vulnerable. Zonebased firewall sample configuration cisco forum faq.
May, 2014 in this article we have begun our fourth lab which is on zone based firewall. Zonebased policy firewall also known as zonepolicy firewall, or zfw changes the firewall configuration from the older interfacebased model to a more flexible, more easily understood zonebased model. Under this new model, interfaces are assigned to zones, and then an inspection policy is applied to traffic moving between the. Interfaces will be assigned to the different zones and security policies will be assigned to traffic between zones. Zonebased policy firewall design and application guide. Traffic between a zone and a nonzone interface is always dropped. Dec 27, 2010 zone based policy firewall also known as zone policy firewall, or zfw changes the firewall configuration from the older interface based model to a more flexible, more easily understood zone based model. Cisco first implemented the routerbased stateful firewall in cbac where it used ip inspect command to inspect the traffic in layer 4 and layer 7. Zonebased firewalling on cisco ios best path consulting.
This move to the cisco ios zone based policy firewall changes the firewall from an interface based model to a more flexible, easiertounderstand, zone based configuration model that helps improve performance as well. Firewalls are typically implemented on the network perimeter, and function by defining trusted and untrusted zones. Deploying zonebased firewalls digital short cut cisco press. Traffic between interfaces in the same zone is blocked unless you configure the same security permit command. Nov 07, 2017 which statement about zone based firewall configuration is true. Primarily, what we want to find out is what address inside local, inside global, outside local, outside global to use when creating firewall policies. Jun 11, 2014 though ciscos zonebased firewall zbf method of securing networks via ios a router has been around for several years i decided it was time to do a through study of the technology and do a writeup.