To solve this problem addresses, the Internet designers reserve a portion of the IP address space and the naming of this space as a private address space. An IP address in private address space is never given as a general address. IP addresses in private address space known as private addresses. Using private IP addresses, you can provide protection from network hackers.

Because IP addresses on the private address space will never be provided by the Internet Network Information Center (InterNIC) as a general address, then the route in the Internet router to a private address will never exist. Private addresses can not be reached on the Internet.

Therefore, when using private IP addresses, you need some type of proxy or a server to convert a number of private IP addresses on your local network into public IP addresses that can be routed. Another option is to translate private addresses into public addresses are valid with the network address translator (NAT) before it is sent on the Internet. Support for NAT to translate public addresses and private addresses allows the connection networks, home office or small office to the Internet.

NAT hides the IP addresses that are managed internally from external networks by translating private internal addresses to public external addresses. This reduces the cost of the registration IP addresses by allowing their customers to use unregistered IP addresses internally, through a translation into a small number of registered IP addresses externally. It also hides the internal network structure, reducing the risk of denial of service attacks against internal systems.

Power over Ethernet is required to perform the injection power supply to the Wireless In A Box is mounted on a tower, POE beneficial to reduce power losses (losses) due to the use of cables and connectors. Lets have look on it.

Actually there are some devices that are commonly using it, which as described above wireless access point, and telephone or fax machine. The POE devices are quite small, and yet functionable, as you could see from the image above.

POE using 2-pair UTP cable is not used, one pair for injection + (positive) power and a pair for injection – (negative) power, used the cable pair (a pair) to avoid loss of power due to cable loss.

Note that the most crucial problems in the manufacture of POE is how to prevent the occurrence of short, because the cable and power connector cross section of small and easily moved or are interested in, cover it with wax or gel insulator so that each point of connection is protected from short power.

Although you do could buy POE devices, but some people are trying to build it their own.

As you could see above, some using the positive power and negative power and connect it directly to power sources, and there it goes, your own home made POE, but always consider the risk that I have mention earlier.

A hardware firewall is a device which sits between your computer and the internet. At home for example it could reside on a broadband router which is used to share your internet connection with a number of computers. One of the advantages of a hardware firewall is that it can be used to protect more than one computer at a time. For this reason hardware firewalls are deployed in corporate networks. For home users who own just one computer a personal firewall is more commonly used and more cost effective.

A personal firewall is a software application that monitors and can block the flow of data between the internet and your computer. The firewall is a key part of your computer security set up. It prevents hackers from gaining access to your computer using an internet connection.

Hackers gain access to your computer through open ports that are used by your computer to communicate with the internet. The most basic firewall programs, like Windows XP’s firewall, monitor and can block “inbound” traffic by closing these ports. If theses ports are closed a hacker cannot access your computer directly via the internet.

More advanced firewall programs like products from ZoneLabs or Symantec also monitor and can block “outbound” traffic. This extra level of security is important and is worth investing in. For example, if malicious software like a Trojan Virus or spyware were installed on your computer without your knowledge the firewall would alert the user when it tried to connect to the internet and prevent it communicating with its host.

A firewall usually works at two basic levels. Firstly, packets of data are analysed based upon IP address and content to see whether they comply with a set of rules which a user can input to. The second level the data is analysed is at the application level. The firewall determines whether an application can send and/or receive data and the port which it should be communicating through.

The firewall “learns” through continuous interaction with the user. It seeks user approval from programs when they first come in to contact with the firewall. Most firewalls also allow the user to allow or block applications through a stored list of program which can be accessed through the firewall’s user interface.

There are a number of sites which will help test your firewall’s effectiveness. A number of these sites are run by security software vendors so it is recommended you test using an independently run site to double-check any results. One of the best independent test sites is run by The Gibson Research Corporation. They offer a free test called “Shield Up!” which can be found at their website – http://www.grc.com. The test checks a number of well-know and vulnerable ports on your computer and then provides some useful additional information to help improve your security while online.

It is important to remember that the firewall is only part of your computer security and does not negate the need for a good anti virus solution, a spyware removal tool and a degree of caution / common on sense on the type of websites a user visits. For example, the firewall will not scan for viruses or remove them from your computer.

Packet filtering is one method that works by examining data packets as they pass through the firewall at the network layer. The firewall examines where the packet was sent from and its intended destination to determine whether it’s safe to let it into your network. A set of criteria is used to determine safety. This method is usually a part of a firewall in a router. Firewalls that use packet filtering can disable information from traveling to and from particular ports, but they are somewhat limited because they do not examine the actual data that is transmitted. They are, however, inexpensive and usually do not interfere with network performance noticeably.

Circuit level gateway and application level gateway are two other methods employed by firewalls. These methods only permit data into a protected network if that data was requested by a computer inside the network. The circuit level gateway method is primarily used by cable/DSL home routers and has the disadvantage of permitting any type of data though the firewall that was requested from inside. It does not examine the content of the data only the port address and port information. Application level gateway (proxies), on the other hand, does examine different types of data at the application level. This method offers the advantage of preventing direct contact between inside and outside sources because everything passes through the proxy. This method offers a high level of security, but can cause noticeable network performance issues. Additionally, these type of firewalls need to be manually configured on each client computer.

Stateful inspection firewalls combine elements of packet filtering and both gateway methods. They both filter packets at the network level and the application level. Contact between inside and outside sources is permitted with this type of firewall, so it tends to remain transparent. Stateful inspection uses algorithms instead of proxies to identify data. These are arguably the best firewall systems because they offer the best of all worlds, but they are usually very expensive and have to be administered by experienced personnel.

If you are looking for a Firewall to provide superior protection for your home or business network, Comodo Firewall Pro is the answer. This Free Firewall Software features packet filtering in combination with outbound application filtering at the network layer. It works proactively to prevent malicious software from ever installing on your computer and has highly configurable features to customize your security options. Comodo Firewall Pro block Trojans, spyware and viruses and prevents any unauthorized access to your computer or private network. It has an intuitive user interface and is suitable for all levels of experience from beginners to advanced users.

Start with a description of your current infrastructure:
[ ] Inventory all equipment.
[ ] Make a list of vendors contact data and account numbers.
[ ] Create a detail network map.
[ ] Make a list of the tools and applications you currently use and what they do.
[ ] Document any special configuration.

Tip: Consider taking a picture of the setup to help others visually identify the setup… Of course, this really only helps if you’re lab isn’t row-after-row-after-row of the same rack-mounted guys.

Preventive Maintenance:
List activities you can do here. For example, think about expected life of the equipment, budget for new equipment, additional capabilities for the system (planning for expansion), and how to find deficiencies in your system.

Maintenance Procedures:
[ ] Start a log book for keeping records of all activities.
[ ] Set a time (downtime) when you can take down the network.  Example: last Friday of the month from 1am – 3am.

Server Maintenance
[ ] Check Hardware – clean when necessary (machines, cables, switches, battery backup).
[ ] Review logs for errors.
[ ] Run MS Baseline Security.
[ ] Make sure Antivirus protection up to date.
[ ] Disk Cleanup & Defrag.
Ask the question: How many of these activities can be automated using Windows Task Scheduler?

Updates
Install only during downtime. Before running updates make sure you backup the machine. Plan ahead what updates you need to run (Microsoft, Firmware and other utilities).
Try out: Windows Server Update Service (WSUS).

Health and Performance Monitoring
[ ] What data do you want to collect?
Current performance, identify incidents, unusual traffic/congestion, etc.
[ ] What are you currently using?
[ ] What are the steps or checks to be done here?
Tip: Run tests on a healthy network and compile data that you can use to compare against results in the future.

Power Failure
In the case of a power failure, what happens to your computing environment. Sure you have a UPS, but if the power fails and you’re not around to properly shutdown the system, what then? Consider setting up a program that detects when the UPS battery is on and automatically shutdowns the machine. Finally, test to see if the UPS works.

Backups
[ ] Where are you storing the backups?
[ ] Write instructions for labeling and storing all backup files.
[ ] Test the restore process, make sure the backup works.
[ ] Create a schedule and have it set to automatically run.

Disaster Recovery Plan:
Create scenarios is probably the best to way to understand dependencies, the impact of a failure, and identify critical components.  For each scenario think about how you will recover data, if there’s a redundant system to switch to, pirorities, etc.

Who’s Responsible for What?
Last but not least…assign people to the task that you define.