Technical Articles and Issues for the IT Specialist
This Blog is a compilation of News and Technical articles for the Information Technology (IT) Specialist. Most articles are picked up from online publications (credits included), others are technical support experience.
Category 5 also has 4 twisted pairs of copper wire terminated by RJ45 connector. Category 5 cable has a bandwidth of up to 100 MHz and speeds up to Gigabit (1000 Mbps). Category 5 cable can be used for ATM, token ring, Ethernet 1000Base-T, 100Bast-T, and 10Base-T networking. Cat5 is one of five grades of UTP cabling described in the EIA/TIA-586 standard.
Category 5 cable comes in two versions: UTP Cable (Unshielded Twisted Pair) and ScTP Cable (Screened Twisted Pair). Catetory 5 UTP cable is commonly used in the United States, whereas ScTP Catetory 5 cable is mostly common in Europe only.
Cat5e Cable
Category 5e is an enhanced version of Category 5 (Cat5) cable, developed by TIA/EIA to improve certain cable characteristics important to Gigabit Ethernet operation, for example, it adds specifications for far-end cross-talk. It supports 1000Base-T Gigabit Ethernet.
Cat 5e (which stands for Category 5, enhanced) cable goes along the same lines as basic Cat 5, except that it fulfills higher standards of data transmission. While Cat 5 is common in existing cabling systems, Category 5e has almost entirely replaced it in new installations. Cat 5e can handle data transfer at 1000 Mbps, is suitable for Gigabit Ethernet, and experiences much lower levels of near-end crosstalk (NEXT) than Cat 5.
Cat5 and Cat5e cables look the same, but Cat5e cable is manufactured with a higher standard to allow for higher data transfer rates. The most common type cable used in a network is Cat5e. Cat5e cable was formally defined in 2001 in the EIA/TIA-568B standard, which no longer recognizes the original Cat5.
Cat6 Cable
Category 6 cable is also called Cat6 and it has a bandwidth of up to 250MHz. It is the 6th generation of twisted pair Ethernet cabling defined by ANSI/EIA/TIA. It has 4 pairs of copper wire and all 4 pairs are used in Gigabit Ethernet applicationis. Cat6 cable is backward compatible with the Catetory 5, Catetory 5e, and Category 3 cable standards.
Category 6 cabe is constructed with even higher standards than Cat5e. Category 6 cable may have a center divider to separate the pairs inside the cable.
Catetory 6 cable is ideal for supporting 10 Gigabit Ethernet. Since technology and standards are constantly evolving, Cat 6 is the wisest choice of cable when taking any possible future updates to your network into consideration.
If you compare Cat6 with Cat5 and Cat 5e, you can see that Cat6 features more strict specifications for crosstalk and system noise. Cat6 can be used for 10BASE-T Ethernet, 100BASE-TX Fast Ethernet, 1000BASE-T/1000BASE-TX (Gigabit Ethernet) and 10GBASE-T (10-Gigabit Ethernet).
You can have up to 100 meters Cat6 cable in 10Base-T, 100Base-TX, and 1000Bast-T application in the horizontal cabling run. This 100 meters includes up to 90 meters of solid cat6 cable between patch panels and work area outlet, and up to 10 meters of stranded Cat6 patch cables from work area outlet to the computer or server.
For 10GBase-T Ethernet applications, you can have up to 55 meters Cat6 cable in the horizontal run.
Some businesses and homes have installed Cat6 cable so that they are prepared for additional bandwidth requirements int he future. Applicationis such as video, video conferencing, and gaming use a large amount of bandwidth.
Cat6A Cable
Whereas Cat6 cable only supports up to 55 meters maximum length when used for 10GBASE-T Ethernet; Cat6A cable, or Augmented Category 6, is certified to 500 MHz in bandwidth and has improved alien crosstalk characteristics, allowing 10GBASE-T to be run for 100 meters just as the same distance as 10Base-T, 100Base-TX, and 1000Base-T Ethernet.
Colin Yao is the sales manager and an expert on fiber optic technologies and products. He is currently with Fiber Optics For Sale Co. which is one of the largest distributors of Cat5e, Cat6 bulk Cables, Cat5e and Cat6 Patch Cables and more.
JERUSALEM — Hackers have launched an assault on Israeli websites, but the damage has been minimal as the Jewish state is prepared to fend off such attacks, one of the country’s top cyber experts said on Sunday.
The hackers associated with the activist group Anonymous reportedly hit the websites of the premier’s office, the defence ministry, the education ministry and the Central Bureau of Statistics, among others, but all appeared to be running normally.
“As of midday (0900 GMT) the sites of the government of Israel are available to the public, as they have been all weekend,” the finance ministry said in a statement.
It said the education ministry site had been temporarily out of action “because of a technical fault which has been fixed.” It did not elaborate.
Later on Sunday, the foreign ministry website was also “paralysed for a few moments before returning to normal,” the finance ministry said, warning of possible slowdowns or temporary cuts on official sites.
Speaking to army radio, Professor Yitzhak ben Israel, head of the National Council for Research and Development, said the scope of the damage to Israeli sites was “more or less non-existent”.
“That’s because of our preparedness in advance,” said Ben Israel, who founded the National Cyber Bureau which operates out of the office of Prime Minister Benjamin Netanyahu.
Ben Israel said it was highly unlikely that Anonymous was seeking to do real damage to the country’s key infrastructure.
“Anonymous doesn’t have the ability, nor is it its aim to destroy the country’s essential infrastructure. If it was, it wouldn’t have announced it in advance,” he said, indicating the aim was probably to stir debate over the Israeli-Palestinian conflict.
“The country was much better prepared than it was a year ago when there was a wave of attacks on the stock exchange and El Al (Airlines) and such sites.
“This time the attack is bigger in its scope and intensity but we are better prepared,” he said, referring to an attack on prominent Israeli websites at the start of 2012.
Guy Mizrahi, co-founder of Israeli data protection consultancy Cyberia, confirmed that Israeli websites had been under a “significant attack” for the past few days.
“Yesterday there was quite a storm, quite a few government sites were hacked and messages were left on some of them, and data was stolen from others,” he told public radio.
“It doesn’t mean that Israel is being thrown off the Internet or that the traffic lights will stop working tomorrow, but it is certainly a significant attack.”
Last November, as Israel and Hamas militants in Gaza faced off in an eight-day confrontation, the Jewish state said it had been targeted by an “unprecedented” mass cyber-warfare campaign.
At the time, Anonymous claimed it had downed or erased the databases of nearly 700 Israeli sites in protest over the assault and over what it said was Israeli threats to cut “all Internet and other telecommunications into and out of Gaza.”
I just tried to do some searching on salary.com. I found the average for a Linux admin is about $82k. However I could not find anything for Windows Server admin, Active Directory Admin, Windows Engineer, etc.
But based upon my own experience being a Windows Admin in the past, they do tend to make less than any *nix admin. However, I have also found that most Windows admins have a lower skill set compared to most *nix admins. Their understanding of how networks, monitoring and SANs work is usually very poor.
Lastly, the costs for Microsoft licensing are just insane. I mean a standard windows server OS license is in the range of $900 per server these days. Plus on top of that you need CAL's for any PC that will connect to that. Add on the costs for web services CAL's, SQL server per/CPU licenses, Exchange services, Exchange CAL's, Windows management services, Windows Identity Manager, etc. And you need to refresh every couple of years. Pretty pricy if you ask me. Most Linux OS's are free. Many applications that you can run on top of Linux that can do the same things as Windows are free, nginx, apache, LDAP, mySQL, etc.
I would, however, not recommend Linux for the desktop. It is too clunky for most users and the application range is not as robust or well developed. Windows 7 and MAC OS would be my choice for the desktop.
As far as monitoring the *nix space, there are many solutions out there that are also free, such as OpenNMS, Nagios, Zabbix, OpsView, etc. Add on top of that a centralized logging solution, you can pretty much run any large company this way. With the correct policies in place for how to build and monitor your environment, it makes it a breeze.
The real problem lies in the way management sees the world of IT and support. They think that if they have not paid for something, then there is no outside expert resolution for issues. They want that nice warm fuzzy feeling they get that if something goes wrong and their admins can't figure out why things are not working, and they can call up Microsoft and get some real support. I remember a story about a corporate legal department who came across a GNU license agreement from a vendor. They had no idea how to deal with it and wanted to add all sorts of liability clauses about possible future copyright and licensing conflicts. It was just nuts.
But in a final note, and don't get me wrong, Microsoft makes some amazing products. And the out of the box, the tight integration between products is really solid. Windows server is a very good product and AD is a really good directory service. I've used ISA and TMG servers and they are stellar firewall/proxies.
In the end, every organization is different and has different needs.The IT systems they depend on are just tools. And the tools will be specific to that organization. If they use a lot of nails to do the work, they should buy hammers. If they use a lot of screws to do their work, they should use screwdrivers. You could probably go the opposite way, and it might work, but there would probably be a lot of damage and it would nto be very efficient.
Distro guide Linux, it is said, is all about choice. Indeed, the ability to choose, well, pretty much everything, is probably the best thing about Linux. But the huge variety from which you can choose - ranging from distro and desktop to window manager - can also be overwhelming for newcomers.
If you've ever thought about abandoning Windows or Mac OS X for Linux, but stopped short because you weren't sure which variety of Linux to choose, this guide is for you.
It would be impossible to filter through every single Linux distribution and attempt to find the definitive one for every situation. There are simply too many distros out there - DistroWatch, a site devoted to tracking such things, lists hundreds of distros you can choose from.
Noobs will likely be best off sticking with one of the "major" distros. That is, distros with a large user base and a lot of developers working hard to improve them on a regular basis. Currently that means Ubuntu, Mint, Fedora, OpenSuSE and perhaps, for those that want more of an adventure, plain Debian.
While I suggest actually installing a big-name distro to start with, that doesn't mean you shouldn't feel free to experiment with distros of all shapes and sizes. In fact, just because you've settled on one distro for a while doesn't mean you can't jump ship whenever you want. Just install VirtualBox and try out any distro that catches your eye in a virtual machine. If you find one you like better than your current choice - install it. It's that simple.
So how do you find the right distro for you? First off you need to figure out what's important to you. Do you want something where everything works out of the box or are you looking for something where you can customise every detail of the user interface? Do you want only free software or are you okay with proprietary drivers and non-free apps like Adobe Flash?
Figure out what your priorities are and then see how each distro addresses them.
In my experience there are three good indicators of how well a distro will suit the Linux newcomer switching from Windows.
The first is, how big and how active is the community around the distro? And I don't just mean the user forums on the distro's website, but the global community of users, bloggers, IRC chatters and so on. If you're new to Linux you're going to have questions. Sometimes the answers you need may be in the documentation, but more often than not you'll turn to Google for help and that's where popular distros with lots of users and dedicated sites can be a huge help. Want to know how you can customise Ubuntu? There are dozens of blogs out there that can walk you through the process. Need to know why Gnome Do isn't working quite the way you'd like in Mint? Again, dozens of sites that can help.
When it comes to active, helpful communities, it's hard to beat Ubuntu and its cousin Mint. Fedora also has a rich community, though there don't seem to be quite as many Fedora blogs. OpenSuSE seems to be a distant third choice when it comes to community, though that may be because it has some of the best documentation you'll find in a Linux distro, which means there's less call for in depth tutorials elsewhere.
The second thing to look for in any prospective Linux distro is the software setup, namely: how good is the software manager and how big are the distro's software repositories?
There are thousands and thousands of open-source applications waiting for you in Linux land, but that variety is worthless if you can't find the best app for your needs. To do that you need a software manager with powerful search features and preferably some extras like user ratings and ideally some screenshots.
And of course you need access to a wide variety of apps. Adding new repositories to your list of software sources is not terribly difficult, but ideally you shouldn't need to do that when you're just starting out with Linux.
Again you'll find that Mint and Ubuntu are the standouts here. Both come with a wide variety of the basic apps pre-installed, and offer easy access to all the multimedia codecs and proprietary drivers you might need. Both also have very easy-to-use software managers.
OpenSuSE likewise has a slick software center and offers a large selection of apps.
Fedora doesn't rank quite as high in terms of the software installation interface, which lacks a powerful search function. Fedora does have a great selection of software available, but finding it and installing it can sometimes be a chore.
In an unexpected and exciting twist for the PC industry, Dell — pending regulatory and stockholder approval — has been sold to Microsoft, Silver Lake, and Michael Dell himself for $24.4 billion. Michael Dell remains the largest shareholder with 16%, and will continue to run the company. Microsoft’s part of the sale totals $2 billion, though big questions remain about how Microsoft will be involved in the newly-private company.
The best question to ask at this point iswhy Dell is going private. The short answer is because the PC is slowly dying, and so is Dell’s stock value. While its stock grew in value until 2005, Dell’s stock has steadily declined ever since. Dell has tried to reverse this slide for years, by shaking things up with acquisitions and a shift of focus to enterprise hardware and services, but seemingly these changes haven’t been enough to right the ship. Here we are: 25 years after debuting on the stock market, Michael Dell is taking his company private again.
What does Dell hope to achieve by going private? In short, it needs some time away from the public limelight to work on some truly innovative products. One of the biggest problems of being a publicly traded company is that you live and die by your quarterly results — but products can take a lot longer than three months to develop. In essence, Dell might want to spend 12 months and billions of dollars developing an awesome new product — but with nothing to show for it in the intervening window, except for more losses, the company’s stock value would take a dive. By going private, Dell can ignore the ire of Wall Street and do whatever it wants. (See: Dell needs a better business strategy, not a buyout.)
Takeaway: The command line is often the best place to resolve Windows 7 desktop problems. These basic commands will help speed your troubleshooting tasks.
Holiday rerun: An oldie-but-a-goodie, these command-line basics topped the list of popular troubleshooter posts last year.
PC troubleshooting is becoming less common in larger organizations, but consultants and techs in smaller shops still have to get their hands dirty identifying and fixing desktop problems. Oftentimes, troubleshooting Windows 7 means delving into the command line. Here are 10 fundamental Windows 7 commands you might find helpful.
Before I begin…
This article is intended solely as an introduction to some useful troubleshooting commands. Many of them offer numerous optional switches, which I won’t cover here due to space limitations. You can find out more about each command by checking out TechNet’s command-line reference.
1: System File Checker
Malicious software will often attempt to replace core system files with modified versions in an effort to take control of the system. The System File Checker can be used to verify the integrity of the Windows system files. If any of the files are found to be missing or corrupt, they will be replaced. You can run the System File Checker by using this command:
sfc /scannow
2: File Signature Verification
One way to verify the integrity of a system is to make sure that all the system files are digitally signed. You can accomplish this with the File Signature Verification tool. This tool is launched from the command line but uses a GUI interface. It will tell you which system files are signed and which aren’t. As a rule, all the system files should be digitally signed, although some hardware vendors don’t sign driver files. The command used to launch the File Signature Verification tool is:
sigverif
3: Driverquery
Incorrect device drivers can lead to any number of system problems. If you want to see which drivers are installed on a Windows 7 system, you can do so by running the driverquery tool. This simple command-line tool provides information about each driver that is being used. The command is:
driverquery
If you need a bit more information, you can append the -v switch. Another option is to append the -si switch, which causes the tool to display signature information for the drivers. Here’s how they look:
driverquery -v
driverquery -si
4: Nslookup
The nslookup tool can help you to verify that DNS name resolution is working correctly. When you run nslookup against a host name, the tool will show you how the name was resolved, as well as which DNS server was used during the lookup. This tool can be extremely helpful when troubleshooting problems related to legacy DNS records that still exist but that are no longer correct.
To use this tool, just enter the nslookup command, followed by the name of the host you want to resolve. For example:
nslookup dc1.contoso.com
5: Ping
Ping is probably the simplest of all diagnostic commands. It’s used to verify basic TCP/IP connectivity to a network host. To use it, simply enter the command, followed by the name or IP address of the host you want to test. For example:
ping 192.168.1.1
Keep in mind that this command will work only if Internet Control Message Protocol (ICMP) traffic is allowed to pass between the two machines. If at any point a firewall is blocking ICMP traffic, the ping will fail.
6: Pathping
Ping does a good job of telling you whether two machines can communicate with one another over TCP/IP, but if a ping does fail, you won’t receive any information regarding the nature of the failure. This is where the pathping utility comes in.
Pathping is designed for environments in which one or more routers exist between hosts. It sends a series of packets to each router that’s in the path to the destination host in an effort to determine whether the router is performing slowly or dropping packets. At its simplest, the syntax for pathping is identical to that of the ping command (although there are some optional switches you can use). The command looks like this:
pathping 192.168.1.1
7: Ipconfig
The ipconfig command is used to view or modify a computer’s IP addresses. For example, if you wanted to view a Windows 7 system’s full IP configuration, you could use the following command:
ipconfig /all
Assuming that the system has acquired its IP address from a DHCP server, you can use the ipconfig command to release and then renew the IP address. Doing so involves using the following commands:
ipconfig /release
ipconfig /renew
Another handy thing you can do with ipconfig is flush the DNS resolver cache. This can be helpful when a system is resolving DNS addresses incorrectly. You can flush the DNS cache by using this command:
ipconfig /flushdns
8: Repair-bde
If a drive that is encrypted with BitLocker has problems, you can sometimes recover the data using a utility called repair-bde. To use this command, you will need a destination drive to which the recovered data can be written, as well as your BitLocker recovery key or recovery password. The basic syntax for this command is:
repair-bde -rk | rp
You must specify the source drive, the destination drive, and either the rk (recovery key) or the rp (recovery password) switch, along with the path to the recovery key or the recovery password. Here are two examples of how to use this utility:
The tasklist command is designed to provide information about the tasks that are running on a Windows 7 system. At its most basic, you can enter the following command:
tasklist
The tasklist command has numerous optional switches, but there are a couple I want to mention. One is the -m switch, which causes tasklist to display all the DLL modules associated with a task. The other is the -svc switch, which lists the services that support each task. Here’s how they look:
tasklist -m
tasklist -svc
10: Taskkill
The taskkill command terminates a task, either by name (which is referred to as the image name) or by process ID. The syntax for this command is simple. You must follow the taskkill command with -pid (process ID) or -im (image name) and the name or process ID of the task that you want to terminate. Here are two examples of how this command works:
