RFC 959 specifies the commands that a minimum implementation (12/06/2007)
(...) The following commands are the minimum implementation required by RFC 1123, plus EPSV and EPRT, which have additional support for IP v6 addresses. The commands included in RFC 959’s smaller subset are noted as well. ACCT account The ACCT command identifies a user account. (...)

Four Rules for Securing Your Devices and Local Network (12/06/2007)
(...) The actions will vary with the device, the firmware, and the security needs of the computers in any local network the device attaches to. Use a Firewall A firewall is the first line of defense against unauthorized access to the resources of your device and local network. Chapter 4 introduced firewalls and explained the need to configure them to allow a device to function as a server on the Internet. (...)

Using Your Policies to Create Firewall and VPN Configurations (11/20/2007)
(...) In other situations in which security policies are not an afterthought, it is common to find that those policies are outdated and probably had little or no impact on the product selection or configurations of their security solutions.The most successful organizations with respect to strong security have a commonality between them security policies.They review, update, and leverage best practice security principals when selecting and configuring their security solutions. (...)

Writing Logical Security Configurations for VPN (11/20/2007)
(...) General Security for Firewall Configurations Anything that relates to the secure deployment of your firewall devices should be documented in this section.We recommend using a spreadsheet similar to the example following. It will allow you to convert your policies requirements into logical configurations in an easy way. (...)

Determining who needs remote access to your VPN (11/20/2007)
(...) Access controls should be specific and related to the requirements defined by your written security policies. Some additional best practice recommendations for remote VPN users include: - Grant access to user groups and not individual users. - Implement access control, granting access only to those resources that are required. (...)

Attacks can be divided into three main categories (11/20/2007)
(...) DoS attacks typically involve running a script or a tool, and the attacker does not require access to the target system, only the means to reach it. In a Distributed DoS (DDoS) attack, the source consists of many computers that are usually spread across a large geographic boundary. Recognizing Network Security Threats In order to effectively protect your network, you must consider the following question: From who or what are you protecting it? In this section, we approach the answer to that question from three perspectives: - Who are the people that break into networks? - Why do they do what they do? - What are the types of network attacks and how do they work? First we look at intruder motivations and classify the various types of people who have the skill and desire to hack into others’ computers and networks. (...)

System and Software Exploits (11/20/2007)
(...) It is very important for network administrators to stay up-to-date in applying these fixes and/or service packs to ensure that their systems are as secure as possible. Trojans,Viruses, and Worms, Oh My! Intruders who access your systems without authorization or inside attackers with malicious motives, could plant various types of programs to cause damage to your network.There are three broad categories of malicious code:Trojans, viruses, and worms. (...)

Types of attack and protocols (11/20/2007)
(...) - Outsiders who have grudges against the company, such as dissatisfied customers or employees of competing companies who want to harm or embarrass the company - Outsiders who have personal grudges against someone who works for the company, such as employees’ former girlfriends or boyfriends, spouses going through a divorce, and other relationship-related problems Luckily, the intruders in this category are generally less technically talented than those in the other two groups, and their emotional involvement could cause them to be careless and take outrageous chances, which makes them easier to catch. Back to Basics Transmission Control Protocol/Internet Protocol Transmission Control Protocol/Internet Protocol (TCP/IP) is the network protocol that pushes data around the Internet. (Other protocols you may have heard of are Windows NETBeui, Mac Appletalk, and Novell IPX/XPS, however none of these concern us. (...)

Attacks over TCP and UDP ports (11/20/2007)
(...) You will never find a legitimate FTP server listening on port 80. Ports 1 to 1023 are considered well-known ports, and have clearly defined IP’s. Ports 1024 through 49151 are registered ports. (...)

Application Proxy and Gateway Firewalls (11/20/2007)
(...) This offers great protection to the servers, because there is no direct interaction between the source and the destination. In addition, the proxy is greatly hardened against attacks and has a very small attack surface. It is very difficult for a hacker to take control of an application proxy firewall. (...)

The inspection of TCP IP packets (11/20/2007)
(...) Therefore, if the packet has inconsistent information concerning its origins, it is unlikely that it is legitimate and is dropped. 3. The firewall compares the ports and addresses to the ACL, and either clears the packet for further processing or drops the packet. (...)

Lower Data Transfer Rates Than a Packet Filter (11/20/2007)
(...) Lack of Fine Control Fine control of application proxies is lost in favor of better performance. Stateful inspection firewall software is written to be generic (i.e. (...)