Network Security - Internet Content Filtering Primer

  Lots of companies employ some sort of Internet firewall, but schools have a unique obligation to provide more extensive Internet content filtering on their student-use workstations. Content filtering can be applied in a variety of methodologies, and most content filtering technologies use a combination of multiple methodologies. Content filtering may be used to block access to pornography, games, shopping, advertising, email/chat, or file transfers, or to Websites that provide information about hatred/intolerance, weapons, drugs, gambling, etc.

The simplest method of providing content filtering is to specify a blacklist. A blacklist is nothing more than a list of domains, URLs, filenames, or extensions that the content filter is to block. If the domain Playboy.com was blacklisted, for example, access to that entire domain would be blocked, including any subdomains or subfolders. In the case of a blacklisted URL, such as, en.wikipedia.org/wiki/Recreational_drug_use, other pages of the domain might be available, but that specific page would be blocked. Often wildcards can be employed to block vast sets of domains and URLs with simple entries like *sex*. Blacklisting can also be used to prevent software installations by blocking access to files, such as */setup.exe, or to prevent changes to the computer by blocking potentially harmful file types, like *.dll or *.reg. Since content filters can't yet differentiate between art and porn, many content filters are also configured to block graphic file types, such as *.gif, *.jpg, *.png, etc.

A whitelist is the opposite of a blacklist; it's a list of resources that the content filter should allow to pass; like a bouncer at the velvet rope, the content filter blocks any resources not specified on the whitelist. Blacklists and whitelists may be used in conjunction with each other to provide more granular filtering; the blacklist could be used to block all graphic file types, for instance, but the whitelist could be configured to override the blacklist on images coming from specified, moderated or sponsored, age-appropriate image hosting services. Blacklisting and whitelisting are quick and easy ways to determine whether or not a particular Website should be displayed. Checking a Website against a list isn't processor-intensive, so it can be performed quickly, but it also isn't robust in that new Websites are constantly popping up, and there's no way anyone could ever stay on top of adding all of the bad ones to a blacklist.

So what do we do about that continual stream of new Websites coming online? That's where more advanced filtering methodologies come into play. Parsing can be used to search for particular words or phrases in a Webpage www.scoutdns.com. Rather than rely solely on filtering by address, the content filter downloads the requested Website (unless immediately blocked by a blacklist) and reads every line of it, scanning for bad words or phrases. A list of bad words or phrases is specified, conceptually like a blacklist, but this list would be checked for any matching patterns in the Webpage, requiring more processor time, and slowing down the serving of Webpages. (In fact, I'm sure that at this very moment there are already a few content filters balking at displaying this very article simply because it includes the word sex in the previous paragraph, and if that doesn't do it, check out what's coming next...) A typical list of bad words and phrases might include "boobies," but since Web authors are just as interested in getting their content past filters as administrators are in keeping it out, it may also be necessary to include odd-seeming varieties, such as b00bies, boob!es, or boobie$. Filtering may be set to block any pages that include any of the bad phrases, or phrases may be assigned point values and the filter could be set to block any pages that exceed a certain point threshold.

The next methodology of content filtering is called context filtering, and it picks up where word and phrase parsing leaves off. The problem with word and phrase parsing is that it's not very smart. It simply acts upon everything that matches a predefined pattern, without regard for context. It might block pages that include the terms "the naked truth" or "chicken breasts," whereas an administrator might not care about either "naked" or "breasts" in those contexts, but might want to block pages including the words "naked breasts," if used together. Even assigning point values and thresholds, it's possible for legitimate Webpages to be blocked.

For example, a Webpage about breast cancer could easily refer to breasts enough times to exceed a point threshold. Context filtering is performed through a variety of proprietary algorithms that are designed by the various makers of Internet content filters. The trick is that they need to balance speed and accuracy; they must download and carefully analyze all of the wording of the requested Webpages to determine whether they are acceptable or taboo, and they need to do it quickly enough to continue to appear as transparent as possible to the users. If they're too quick to judge, they may let through unacceptable content (known as "misses") or block acceptable content (known as "false hits"), but if they're too pensive, users will complain about latency. Building a better algorithm requires more time and money, so frequently the faster and more accurate filters cost more.

Just for the sake of completeness in this treatise on Internet content filtering, I should also mention that there may be other methodologies employed or configurable in various Internet content filtering solutions. Virtually all Internet content filters operate on port 80 (http); most ignore other protocols, but some may be able to apply filtering to other ports, or may be capable of entirely filtering out specified ports, such as FTP or Telnet. (I wonder which port "World of Warcraft" uses...)

Similar to firewalls, I should also point out that Internet content filters come as hardware or software solutions. Hardware solutions are commonly known as "appliances," and software solutions are commonly known as "applications," or "services." Hardware solutions provide for centralized administration. They may cost more, but they perform all of the filter-related processing so as to relieve your servers and workstations from any such responsibilities. They frequently come with subscription services for updates to the blacklist, whitelist, phrase list, and context data, much like antivirus subscriptions provide updates to lists of virus signatures. They may be multi-homed pass-through gateways, or they may work by redirecting traffic to a specified port or destination IP address.

Higher-end models may also include caching to speed up the serving of frequently-accessed resources. Software-based solutions may be server-based or may be installed on each individual workstation. Most server installations offer the same centralized administration as hardware solutions, but of course, they use your processor and RAM to perform the filtering, rather than being a dedicated appliance. Consequently, they may be less expensive. In the case of a workstation installation, besides installing the software on each individual workstation, you may also need to individually configure each workstation, and periodically you may need to individually update each workstation.

Even Microsoft Internet Explorer has a free, simple, built-in Internet content filter - it's called the "Content Advisor," and you can configure it under Internet Options in the Windows Control Panel. It's fine for your kid's standalone computer or a small peer-to-peer network, but is probably inadequate as an enterprise solution. Whether hardware- or software-based, best-in-class enterprise solutions are often Active Directory-integrated, simplifying administration and configuration, and permitting filtering settings to follow users anywhere in the network. Teachers, for instance could have less-restrictive settings, regardless where they log in, while students could still be blocked, even if they sneak into the faculty lounge during recess.

The Best Creatine Supplement

Creatine is on of the most popular supplements for muscle energy among athletes who want to push the limit of what is physically possible. It is actually a natural resource of energy contrary to popular belief. Creatine can be found in meats and fish in small amounts. Using it as a supplement can seriously boost muscle mass in workouts. The best creatine supplement however, is going to be left to the science and facts.

Athletes take creatine supplements before and after workouts to increase their strength and performance during sports. The 2 forms they use are powder mixed into drinks or capsules. Most specialty drinks for bodybuilding include creatine in the list of ingredients. It's much more affordable to buy the powder and mix the drinks yourself. For what 2 drinks cost, you could buy an entire container of powder.

Creatine is naturally present in human body. Normally a person has 120-100 grams of natural creatine in their muscles or other parts of the body. Among the many different types of creatine the most common is creatine mono-hydrate https://www.fletchreviews.com. The reason for this is not necessarily because it's the best creatine but the most widely used. Turns out science has made some interesting discoveries on which is really the best creatine supplement and why.

During exercise or workouts, body uses energy stored in the muscles as ATP (Also known as Adenosine Triphosphate). Stored ATP is being converted to ADP when the body uses up a phosphate molecule in the energy process.

Unfortunately, ADP can't an energy resource for muscle performance. The body in turn uses its stored creatine to change the ADP into ATP in order to be used again as energy in muscle workouts. The body's stores of creatine can be increased by the supplementation of creatine which will help restore ATP much faster. This process works even better when using the best creatine supplement. Since creatine has the ability to donate one of its phosphate molecules, use of the best creatine will improve this process even further. In turn this will boost the amount of muscle performance in length and intensity during exercise and thus it maximizes the workout performance and pushes the limits to muscle building workouts. Building stronger, larger muscles faster.

After taking the loading dose athletes usually take a maintenance dose of 5 grams per day. Taking it with a form of simple carbohydrates will trigger the release mechanism for insulin and help increase the uptake of the best creatine supplement in to the blood stream and into the muscles.

Though no serious side effects of over dosage of creatine supplements has ever recorded, gastrointestinal upset is one of the most common problems due to over taking of creatine supplements. This is the usual M.O for taking too much of any type of supplement. Once your body gets used to the supplement it can really put it to use and begin seeing some results.

Choosing a low quality creatine supplements is a waste especially if your serious about building muscle mass. There is a site that discusses which is the best creatine supplement and why its the best creatine.

If you've been researching the supplement industry for very long, you have probably discovered that most of the products out there are complete JUNK. However, one supplement that has proven time and again to be truly effective is creatine. Still, you must be careful to avoid bogus creatine products, as well.

This article will explain the 3 most essential things you should look for when looking for the best creatine supplement. If you follow these tips, you are sure to spend your hard-earned money on a quality product. At the end of the article, you can find a comprehensive guide to building muscle, including the most crucial information on training, nutrition, and even supplementation.

1. Make Sure You Buy Creatine Monohydrate

When looking for the best creatine supplement, you must first learn what types of creatine are available. There are a few new types of this supplement, the most prominent of which is creatine ethyl ester. Though it is marketed as some great improvement upon the original, it is really just an extremely bitter-tasting, unmixable, higher priced version of basically the same thing.

You should stick with the best creatine supplement, which is the monohydrate variety. This is the supplement on which thousands of tests have been performed, and which countless bodybuilders and weight lifters have found to be the most effective.

2. Avoid Mixed Creatine Supplements

Many supplement companies sell basic creatine products mixed with other, supposedly amazing ingredients. What you must know is that this is really just a marketing ploy to get you to buy creatine at a ridiculously high price.

The ingredients mixed with the creatine are usually just various forms of sugar and starch. While it can be very beneficial to combine your creatine with some type of sugar drink, you should never pay as much for the combination as these companies charge. The best creatine supplement is still the simplest.

3. Only Buy Dirt Cheap Creatine

One of the things that is so great about creatine, and that has allowed it to become the most popular muscle building product, is its extremely low price. You should never, ever pay more than about 10 cents per 5 gram serving. The best creatine supplement will have this cost, or lower. Make sure you compare the price of the whole container to the number of 5 gram servings to get the best deal.