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The meaning of the word Firewall is not clearly defined. Firewalls can be anything from simple packet filters up to complex application level inspections. The more complex a firewall is, the greater is its attack surface and the more it has to protect itself. Some examples of possible attacks against a firewall: If the firewall does virus scanning you can ...


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Is it possible for a hacker to pretend/try to communicate with a service on the server and when the firewall examines the traffic it get's poisoned or taken control of? YES ! It is Possible . I will explain how. Firewalls operate by checking incoming and outgoing traffic against a set of rules. These rules might be based on metadata or real data ( the ...


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Other possibilities are (or could be): exhausting resources on the firewall, leading to a denial of service - e.g. due to a need to keep connection state DNS cache poisoning if the firewall tries to resolve IP addresses XSS on a page denying HTTP connection breaking or poisoning firewall logs (ANSI bomb) or exploiting a software reading the logs


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Yes, definitely. See the Witty worm for an example of a vulnerability in a firewall product that was exploited by a network worm. Firewalls are nothing but software and affected by the same flaw. The more complex the firewall, the more likely it is for a bug to be introduced. For instance, a simple port filtering firewall is very unlikely to be affected by ...


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Docker was just added his own iptables rules before UFW rules see https://docs.docker.com/articles/networking/ for details. to avoid the pb I put DOCKER_OPTS="--ip 127.0.0.1" in my /etc/default/docker. so I bind only to localhost and it's not reachable from the outside.


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This is a very broad question, depending on your setup. If you use SSL from your PC to your mailserver (wich is not administrated by the same guys) and your connection is secure, they can't see anything about your mail, except for the size. If you use unencrypted communication with your mailserver or the mailserver is administrated by the same guys it ...


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"Proxy server" is an imprecise term. You have to think about what the proxy server is protecting to determine where it fits on the network. For example, web proxy servers used to channel outbound web surfing are often placed on internal networks rather than DMZs - their connections are outbound and they pose no additional "threat" to the internal network - ...


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I don't think it would make much of a difference. NAT has nothing to do with security and the firewall should be your primary defense. Having a device provide both firewall and NAT services isn't a security risk by itself. The only potential security risk would be the software and configuration of the device. Since there are so many vendors/products on the ...


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Related but important topic: According to this CentOS hosted page which is about having custom kernels, "CentOS is designed to function as a complete environment. If you replace a critical component, it may very well affect how the rest of the system acts.": http://wiki.centos.org/HowTos/Custom_Kernel See also this Stackexchange-related answer to the ...


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Organizations often have a separate internal dmz, where services such as the proxy server is available for the clients inside the organization. This is however not entirely outside the firewall, but in a security zone with the appropriate firewall policy and often ips. There are many reasons for such a design, and the most important one is that servers on ...


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What you describe is not what is usually called a "proxy". The normal "proxy" is a machine which is close to the client, not the server; communications between the client and the proxy are not normally encrypted (they can be, but that's rare); and when the target server uses HTTPS, then the SSL is between the client and the server, the proxy seeing only the ...



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