The Compaq 6735s is a relatively new addition to HP’s extensive range of laptops. It would be safe to say that with the spec you get with the 6735s it is mainly aimed for office users and those on a budget. However with that being said the performance you get is very good considering the price tag and even some lower end gaming can be achieved easily enough from it.

Look and feel – The case is well built and designed and has a sleek and slim line look to it. You get the standard 15.4″ tft screen which is well attached, the first thing you will notice however is the maximum angle at which the screen will go, you cannot extend it back anymore than 135 degrees. Whilst this might not seem a big issue you might be surprised at how often you might need to extend the screen back further.

The laptop itself is quite light weighing in at 2.5kg which is quite reasonable considering its standard size, the other thing you might notice to begin with is that there is no locking mechanism for when the screen is down and this can cause problems for some! It is also a bit more fiddly to unlock the screen when it’s down.

The 6735s is quite a tricky laptop to clean, above the keyboard you have the built in speaker panel mesh which is a nightmare to clean if you get anything in it! Also the hinge covers will soon gather lots of dust and it’s tricky to get it out of.

The keyboard is well built and like with all HP laptops very easy to use, keys are spaced perfectly apart and require just the right amount of effort to use. As for the touch pad well, let’s just say it’s very sensitive, perhaps a bit TOO sensitive, I have found myself typing away and all of a sudden the mouse has moved position because my hand has hovered over the keypad ever so slightly, this can get a bit annoying!

Display – The screen is probably one of the slight bad points with the 6735s, when you are using it you will probably notice that the contrast is a bit weak and dull, especially so when running on batteries. If you plan on using this laptop outside in the sun then you are going to struggle to see anything unless you have the charger plugged in.

Spec and performance – The 6735s comes in a range of models but by standard you will get an AMD X2 dual core 2ghz processor with 64bit capabilities (should you decide to go down the 64bit operating system route). The lowest spec version will come with 1GB of ram bit you have a maximum capacity of 8GB. As standard, 1GB is quite poor nowadays and will not serve you too well if you’re planning on running any memory intensive applications. Storage will vary but the model I tested was 150GB which for some people will be plenty. You get the usual built in accessories: wireless LAN, 1GB network card, 4 usb ports, DVD writer, modem and card reader.

If you plan on pushing this laptop to the limit then I would probably reconsider. The performance starts to get very sluggish when the CPU is over half load; you will notice jolty response times and once the fan kicks into double speed things start to get very noisy! Not only that but the left hand side of the laptop where the heat sink is will get very warm indeed.

Battery life – The battery life can vary, if the laptop is under minimal load you might be lucky to get over four hours of life out of the 6735s! However, as soon as you start to put the CPU under stress you will soon see the battery life drain and under 75% load you might get just over an hour out of it!

Conclusion – The 6735s is a nice entry level laptop and is probably more suited for the casual user. It has all the features you would need for general laptop use (including a built in webcam!) with good performance and a very decent price tag ($420!). For those who need a laptop for more intensive use they might want to choose a different model as the 6735s struggles under heavy load and doesn’t offer the performance for a more high end user.

Firewalls are an important part of internet security. They guard systems and networks from hack attempts and other malicious unauthorized activity. But how do you the work? To understand this it is important that you understand some basics on how the internet works and how ‘packets’ move around from network to network. Let’s examine this in a bit more detail.

What is a packet? – Simply put a packet is a small collection of data that is sent from one system to another. If a machine wanted to send a one megabyte file to a server it would not be practical in most cases to send it all in one go, so what happens is this data is then split up into packets. These packets are then sent individually, the advantage here is that if one packet fails to send it can easily be resent without needing the rest of the data to also be resent. A packet contains important information to ensure that it arrives where it should do. The most important parts being – the source address, destination address, source port and destination port.

What is a port? – Every single piece of data sent across the internet needs to have a source port and destination port. The source port is generated automatically in most cases by the operating system and is a simple way for your computer to differentiate between two lots of data. For example – let’s say you’re browsing the web and sending email at the same time. When a response comes back to say your email has sent how does the operating system know that this packet is destined for your email client? With the source port of course! Your computer will setup a virtual port for your email client (let’s say 1024) and then when you start browsing the web it will setup another port for this (let’s say 1025)

The destination port is more important, it tells the receiving host what service the packet is meant for. All the common services on the internet (http, email, ftp, telnet) have their own standard ports. Here is a list of some of the common ones:

• Http (Web) : 80
• Sending Email (SMTP) : 25
• Receiving Email (Pop) : 110
• FTP : 21
• Telnet : 23

So when a server receives a packet with the destination port of 80, it knows that this is a web request and it hands the packet to its web service program (IIS or Apache for example).

Now that you know about packets and ports it will be easier to understand how a firewall works.

The basic job of a firewall – A firewall can be either hardware or software, essentially they serve the same purpose, a hardware firewall would physically sit in between your local network and wide area network. A software firewall would sit on a client machine and therefore would only be able to protect that machine it resides on.

A software firewall sits low in the operating system and integrates with the network handler, by doing this it can ‘intercept’ every single packet that goes in and out of your machine. A firewall will usually come with a default set of rules that it must adhere to. These rules will determine what packets a firewall will allow in and out. Typically a firewall might be set to only allow outgoing traffic on certain ports. By doing this only traffic destined for the allowed services would be allowed out. So if a rogue program made its way on your machine and attempted to ‘call home’ on a different port to the ones in your allowed list, it would be blocked.

Whilst this is all good and well, what would happen if this rogue program called home on an allowed port, like port 80? Well the firewall would let it through of course and we don’t want this. This is why many firewall programs will generate rules based on the process name. For example it would allow iexplore.exe to communicate out on port 80, but any other program communicating out would need permission.

Analyzing incoming traffic is probably the biggest job for the firewall, every packet must be examined to see what program it is destined for and whether it should be allowed. Again, most software firewalls will have a list of rules of what to allow and what not to. If a packet comes in destined for a port that is not being used then it will be dropped and logged. The set of rules that a user can customize for a firewall will only offer so much protection, this is why many firewalls will use heuristics to determine if a hack attempt is being made. Many hack attempts will follow patterns that the firewall will determine and be able to establish as a hack attempt. A common example is port scanning – when incoming requests for ports are flying in fast the firewall will usually know that this is a port scan attempt and will then drop all packets from the source host for the next ten minutes.

This kind of pattern detection is what makes a firewall effective at its job. Fixed rules are only effective to a point, if a firewall is challenged with an attack that it doesn’t know about it must be able to detect it and stop it.

So in summary; a firewall is used to analyze every packet coming in and out of an interface and determine whether it should be allowed, packets that are not allowed are blocked. To determine whether a packet is allowed a firewall will follow a set of rules that can be customized by the administrator. Many firewalls also use heuristic detections to stop hack attempts that follow common patterns.

One of the most common tasks of home networking is setting up wireless routers. With Linksys being a very popular brand I have decided to write a step by step guide on setting up a Linksys wireless router. Please be aware that the layout of the configuration pages may vary slightly from model to model, however the concept will always remain the same, as will the terminology used.

To begin with you should understand that there are generally two types of Linksys wireless routers, DSL/ADSL and standard. DSL and ADSL routers require connection to a phone line and a username and password provided by your internet service provider. Standard ones plug directly into your cable modem and or media converter (This is because your internet will usually be delivered by a coax cable and will need converting to Ethernet). I will try and cover both options in this guide.

Firstly let’s get familiar with the back of a typical Linksys router, again your model might vary but the connections will be the same as well as the labels.

The back of a typical linksys wireless router

Firstly on the left is a WAN port, this is the port that connects up to your cable modem via a normal Ethernet cable. If you have a DSL/ADSL router then this WAN port might say DSL instead and will be slightly smaller (rj11). The four ports in the red rectangle are your LAN ports; they are used to connect up devices to your network via a cable instead of wireless. The port on the right is the uplink port; unless you are connecting multiple routers together you don’t need to worry about this! If you are using a cable modem then at this point you can connect a cable from your router’s wan port to your cable modems Ethernet port.

When you first get your router you are going to need to connect to it via an Ethernet cable to configure it, once you have configured it the first time you can access the configuration afterwards via wireless (providing you have setup the wireless network!) Typically most Linksys routers are shipped with the ip address of 192.168.1.1 and to connect up to this via a cable you will need to an ip address in the same range on your computer. So, click start > control panel > network connections. Right click your local area connection and choose properties. Double click tcp/ip from the middle section and click the circle box that says “Use the following ip address” Now configure your address to be 192.168.1.20 and your subnet mask to be 255.255.255.0. Ignore the other settings for now; you don’t need those at the moment.

Once you have configured your address load up internet explorer and type into the address bar: http://192.168.1.1 You should then be prompted with a username and password login, by default most Linksys routers will have their username and password set to ‘admin’ for both, but double check the documentation you get with it just in case.

Once you have logged in you should be presented with a configuration screen. The two things that we need to configure to get you online are your internet connection setup and your wireless network. To start with click Setup at the top and then ‘basic setup’ you should have a screen like the one below:

If you are getting your internet connection from a cable modem then you should leave the top drop down box as Automatic Configuration. If this is the case then your router should be allocated an external ip address and be ready to use. If you are using DSL/ADSL then you will need to change the drop down box to pppoe (point to point protocol over Ethernet) you will then need to specify your username and password that was provided by your internet service provider.

You should also enable the DHCP server at the bottom, you can leave the default values as they are (first address starts at 100 and maximum of 50 address leases)

At this point your router should be connected to the internet and you’re ready to use it, however we still don’t have any wireless! So next click the wireless tab at the top of the configuration page, you should see a screen similar to the following:

Under the basic settings page you need to choose a name for your wireless network, this is the name that will be broadcast so you can identify that it is your network. Once you have picked a name make sure the “Broadcast ssid” option is set to enable. Next click the wireless security tab and you should see something like this:

This part is crucial, I wrote an article on the dangers of unsecured wireless networks just in case you are considering skipping this step! Also I would like to strongly advise you to NOT use WEP here, it is very insecure and can be hacked quite easily with only a small amount of knowledge. For maximum security use WPA or WPA2 personal and make sure you choose a long complex phrase, one with plenty of characters of both lower/upper and numbers.

Once you have setup your security (make sure you write the key down!) click on save settings. The router might need a reboot at this point, if so do it. Once it comes back online you should be ready to go. On your pc or laptop browse your wireless networks and you should see yours listed. Double click it and then you should be prompted to enter your wireless key. Once authenticated your Linksys wireless routers DHCP server should issue you an ip address and you should be ready to start browsing!

Feel free to contact me using the contact page if you’re still struggling.