Incident Response. Firewalls are one of the oldest computer security defenses that continue to remain a crucial foundation of network protection today. A firewall must be correctly installed, updated, and maintained. Firewall rules must also be reviewed semiannually. Network and cardholder data flow diagrams help identify the location of all network devices and how card data flows through each piece of the network.
While analyzing these diagrams, you should be able to study exactly what areas must be protected, and the unnecessary services, protocols, and ports to disable. Learn how to make a card flow diagram. Description of groups, roles, and responsibilities: By documenting who is involved in the firewall process, you ensure those assigned are aware of their responsibilities.
Public Email is via a Linux Proxy which is connected to remotely. Attachments have to be downloaded remotely then can be retrieved after scanning, if needed. In over 4 years, I haven't had a virus beyond the DMZ, unless its still unknown.
So far, viruses were all caught at the Proxy Servers as soon as downloaded. Browsing is via a Proxy machine also, nothing is downloaded directly off the Internet behind the 2nd or 3rd firewall. Ports are reassigned above so the 2nd and 3rd Routers are almost Black Holes. New customer information is pulled to more secure servers daily. All management machines are Linux.
Initially, setting up and Black Listing is time consuming, once the big offenders Microsoft, Google, and NSA are locked out things are easy to maintain. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Ask Question. Asked 7 years, 4 months ago. Active 6 months ago. Viewed 43k times. Improve this question. Jamal 1 1 silver badge 8 8 bronze badges.
I suppose two firewalls could also have trouble working together. It would be nice to know of a concrete instance where two firewalls in series actually saved the day or conversely were of no help whatsoever against a well-crafted attack. Due to the nature of the beast, the first case is likely to be rare and undocumented, the second case is is likely to have occurred quite a few times e. Isn't the encapsulation supposed to be transparent?
Add a comment. Active Oldest Votes. The main disadvantage is cost and maintenance, but in my opinion the advantages outweighs these. Improve this answer. Dog eat cat world Dog eat cat world 5, 1 1 gold badge 24 24 silver badges 44 44 bronze badges. No, the main disadvantage is that you've added another single point of failure in your network.
Also, point of note, but almost all industry-grade firewalls in the market nowadays can handle a DMZ setup with only a single firewall box by maintaining different networks on different ethernet ports. If you worry about single points of failures, redundancy is the option.
In this case, single points of failures are not "random", as it is initiated by malicious intent. What is worst? A denial of service disrupting the whole network, or just the external network? As a rule, No. This is why I give a specific situation in my question. Let's say that an attacker have some exploit for this firewall and he is able to bypass it.
In this case I think that the second FW will be able to prevent the attack. As a rule, you don't exploit a firewall. There's no code you can download that will defeat Juniper firewalls or Cisco firewalls. You bypass a firewall by tunneling your traffic over connections that the firewall is already configured to allow. Kiwy you will find that You attack a connection that already accepts you.
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