Mike Vincenti

Ok... This is a bit crazy. Actually, the only crazy thing about this is that there are just so many crazy people out there like me! I mean... Apple release a totally new device in April called the iPad. It is revolutionary and "magical" and totally creates a whole new genre of device! Not more than a few months later, Apple unveils their updated iPhone. It isn't nearly as ground-breaking as the iPad... or is it? As successful as the iPad was/is; this iPhone which is merely an update to their existing line of cell phones, sells more than 600,000 units in the first day! So much so, that the delivery date of these phones is pushed at first to 2 weeks away and then nearly a month away! Think about it! Over 600,000 people (including myself), slapped down over $400 for a new iPhone that they won't even receive for another month. This kind of success is just incredible. But if you had seen the keynote that Jobs delivered, you'd understand. What other company gets away with presenting the public with a one hour commercial and have people banging at the door to get in? What other company can triumph over last year's triumph again and again? I am only amazed by the consistency and duration of Apple's ingenuity, marketing and development. It isn't just a product. It isn't just a commercial and it isn't just some new gadget. Every aspect works in conjuction with the next. Whether you are talking about their marketing plan, their hardware or their software- you must agree that the cohesiveness of the company as a whole is proven through their own customer's loyalty and acceptance. 

 Apple is not a democracy. This is the epitome of Plato's idea of autocracy. Had Apple been a democracy, we'd be left with mediocrity and quite possible still be carrying around a flip-phone with buttons! Mediocrity doesn't like to change. Although it is the most fair (possibly) in regard to politics, companies, ideas, art and music are often best left to the single individuals that have the capability of performing their true nature unto the world unimpeded by the rest of us- the mediocre folk. But I understand this. And so I am quite happy to pay and wait for my iPhone. It is my way of encouraging, voting for, and approving, the things that I believe in. I do the same thing for any form art- be it technology, music or sport, I pay for it because my penny is my vote. 

  What the heck is a host file and why in the world would you want to modify it? 

  A host file is the file on your computer that resolves domain names. For instance, we are very accustomed to going to websites by name.  But this is a relatively new convenience. Back in the 80s, if you wanted to go to Google's network (let's imagine that Google existed back then), you'd have to enter the IP address. The IP address looks like "24.48.233.121." But we're human and don't identify companies or people by number. So now we use a convention called DNS- Domain Name System. It is the system that maps names with their IP address. So instead of typing 24.48.233.121, we can type in "www.google.com." What happens though, is that your computer goes to another computer (a DNS server) and asks that computer what the IP address is for the requested website. Once the IP address is known, it is very easy to work your way through the huge network called the internet to finally arrive at the computer that is hosting the webpage that you are looking for. 

By the way, a webpage is just a file on a computer and a website is a collection of files that are related. A web browser merely "renders" the file's contents and displays it within the web client. Different web clients render pages a little differently which is why the same site may look a little different between Safari and Firefox.

  Anyway, the two most popular reasons to modify your host file to either block known malicious sites or advertising sites, and to redirect your computer to a specific website upon requesting a page. Here's how you do it:

1. First, open Terminal. It is an application located in your Utilities folder.

2. Once Terminal is up and running, type "sudo pico /etc/hosts"

The "sudo" command invokes root user priveliges. The "pico" command is a common text editor that we are going to use to modify the file "hosts" that is located in the "etc" directory found on the root of the hard drive.

Terminal will then prompt you for the user's password. You must be logged in as an administrator to do this. You'll notice that as you type the password, nothing will appear on your screen. That is normal. Just press "Return" after you type in your password. You should then be taken to the Pico text editor. There is no mouse in Terminal so you must navigate with the keyboard only. Using your arrow keys, place the cursor after the first entry.

3. So once your cursor is blinking right after the "localhost" word, press return to enter a new line. You will then enter the IP address, then hit "Tab" and then enter the web address that you want resolved. Be sure to use the EXACT computer name. 

4. When you are done, hit "Control-X" to exit. It will prompt you to save the file. Hit the key "Y" for yes. When it asks if you want to replace the existing file, again type "Y" for yes. 

5. Then you can type "exit" and finally quit Terminal. You have just successfully modified your host file. 

  Be careful though, you can easily break your machine by doing something wrong. It may be a good idea to save a copy of the original file just in case you need to revert. In order for the changes to take effect, simply restart your machine. Logging out and back in again may work but a restart will surely work.

  In Leopard, you could also just clear the DNS cache by typing "dscacheutil -flushcache" while in Terminal.

  This article will be broken up into different sections so you can skip around to what interests you most. I'm going to start with the Outgoing Mail server because that will be relevant to ALL email setups so you should definitely read that.

OUTGOING MAIL SERVER

  In order for you to send email, you must send your email to a server that knows what to do with email. This is often called an SMTP server. It stands for "Simple Mail Transfer Protocol." It is important to remember that you must have authorization to use someone's outgoing email server. For Optimum Online users, every customer has that access. Their outgoing mail server is:

mail.optonline.net

  So long as you have a cable modem, Cablevision knows that you are a paying customer and therefore lets you send mail through the above server. All others will be denied access.

  If you have a MobileMe account, the outgoing mail server is filled in automatically for you because it is recognized within Apple's Mail that you are a paying customer.

Special Note:

  If you have a laptop and you have Optimum Online you may have no problems sending and receiving email. But once you bring your laptop to your friends house, you might notice that you can't send email anymore. Why? Your friend may have Verizon FiOS or something like that. You can still receive mail because your application (Apple's Mail) can still reach (and check) the incoming mail server. That is never blocked. Only you have access to that account via your username and password. However, the outgoing mail server is configured to use "mail.optonline.net". This will not work at your friend's house because he doesn't have Optimum Online (or a Cablevision modem) and therefore you are denied access to the outgoing mail server. 

How do you get around this?

  Well, you can either use a different email account to send the email, you can logon to the web interface and send mail through a web browser or you can just wait until you're back on the appropriate network (the optonline network). Other systems use a username and password to secure their servers. Cablevision uses their own modem as the key to their network.

INCOMING MAIL SERVER

  Optimum Online makes it convenient for us because their Incoming Mail Server is the same as their Outgoing Mail Server: 

mail.optonline.net

  If you are using a MobileMe account, this information is automatically entered for you. If you are using a Gmail account, I believe the correct incoming mail server is "pop.google.com" or "imap.google.com". Every service has their own servers so you must get this information from them. Otherwise, setting up any email client will be impossible.

USERNAME

  This is usually the part of your email address before the "@" sign. That is the case for Optimum Online. For many other services, it is often your full email address.

PASSWORD

  I've heard so many times from people that they don't have a password for email. That is impossible and extremely unsafe. It is just that their email client was already configured to auto-enter it and so therefore the user never had to enter it again. Please remember your password. Losing it is only going to cause you grief.

Now lets go through some screenshots so you can really see how to set it up.

  The new Stafford Technology Center will be fully open by June.  Finally, I will have a place to teach these Mac courses that I have been doing at a variety of libraries around the island. With the new building, there will be new courses being offered. I personally will continue to teach the Mac Basics course that have been quite popular in the libraries. The building should be open by June and that is when classes will be offered. We have a very nice classroom and each session will be no larger than about 20 people. This will ensure that everyone's questions will be answered and that everyone can engage in the conversation. You can purchase your course online by clicking the "Add to Cart" button below! Or, send me an email for more information by filling out the form to the left.

  This is a rather controversial topic. Although sharing files across the internet could be a totally legitimate way of sharing information, it is usually the primary method of piracy. Because high speed internet access is almost the standard across the civilized world now, piracy has reached all time highs. I'd like to offer my disclaimer immediately and let everyone know that I do not condone piracy. However, I strongly encourage you to read my article in reference to the Recording Industry Association of America (RIAA) and why I personally have no conscience when it comes to sharing music. Keeping in mind that I am myself a musician, I'd like to suggest that the internet and the affordability of technology is rendering record companies more and more useless every day. It is of utmost importance that musicians do NOT sell themselves short when signing a contract. They need not "sell out" as quickly as they did before. However, it is also recognized that the record companies are the gatekeepers AND the key holders of the music industry. Please, just read the article.

  As for software piracy, I love to buy shareware. And I will buy professional applications like Apple's Logic Studio 8 or Adobe Creative Suite when and if I am using them professionally (to make money).

  That being said; here's how to "share" files...

Peer to Peer (P2P)

  Limewire is a file sharing client for the Gnutella network. What it does is this. Upon first launch, it opens up ports on your computer and establishes a "share" folder which others have access to while Limewire is running. It is known as a P2P file sharing application; that is, a Peer to Peer because one computer connects to another computer to download a desired file. What makes Limewire unique is that it is similar to Torrents (later explained) in that it will find other computers with the same file and will download that same file to your computer simultaneously thereby increasing download speeds and efficiency. This is the simplest kind of P2P file sharing. And since it is very easy for anyone to do this, it is the most common form of file sharing. It is also the most virus and spyware prone vehicle known. Bearshare is another popular service that is often referred to as the worst of all virus laden services. Another caveat of these services is that since it takes almost no technical skill, often times the files that you are trying to download either don't work, are of a horrible quality (movies and music), or are false and are actually something else (like spyware, viruses or simple adverstisments for another product or service). I will use Limewire as a "last resort." However, here is a great tip on how to share your files with someone else.

  I had a client who needed to send files to one of her clients. These were huge Photoshop files that she had been working on and in order to collaborate with her client, she had to keep it in the Photoshop format. These files were about 500 MB in size. Emailing was not an option and FTP was too complicated. So this is what I told her to do: I told her to install Limewire on her machine and her clients' machine. She was to name the file that she wanted to share with her client something very obscure and long- something like "aldiwdls;aidja;diaknfiwehniw9". Obviously, no one could guess the name of this file. But she sent the file name to her client via email. When her client started Limewire and searched for that file, low and behold, Limewire began to download it. It was a quick and (very) dirty way to share a file without using FTP.

  Most P2P file sharing applications use commonly known ports to function. If you are at a school or business, these ports can be closed at the router or firewall to disable these services. Keep in mind too that these services suck up a lot of bandwidth so your usage will definitely affect the whole network.

Bit Torrents

  Bit Torrents require a little more expertise but it is still not that hard. All you need is a bit torrent client (like Transmission, Acquisition or BitTorrent) and a few good websites to acquire the torrent (like IsoHunt, torrentz.com or MiniNova.org). Often, doing a Google search for the file you want followed by "torrent" will garnish you a positive result. A torrent is really just a pointer to where the file is. Once you have your client open this torrent, it starts downloading the files requested. The good thing about torrents is that the more people downloading a file, the faster the download! How is this possible? Because even while you are downloading the file, the parts that you have downloaded are now being contributed to the torrent as a whole. So others can download just the parts of the file that you have already downloaded. The more people downloading the file, the more sources available to download from, the faster and more available the file downloads.

  The quality of files are often better because it does take a little skill to offer a torrent. Because of this, the user knows to not compromise quality just for the sake of small file size. It is also nice to have an active forum from which you can read the posts of others who have already downloaded these files. Most times, simply by reading the posts you can decide whether or not you want to spend the time downloading this file.

Newsgroups

  Newsgroups are much more complicated and for the most part, are not free- at least not the better ones. There are 4 main ingredients to utilizing Newsgroups. 1- you need a Newsreader. 2- you need to subscribe to a newsgroup. 3- you need to subscribe to a service that allows you to search for files. 4- You need a program to reassemble all of the parts of the file that you are downloading. Each of these things can cost money. I'm sure you can find a way to do it for free but you get what you pay for.

  One of the ways in which a Newsgroup is judged is by their "retention" period. That is, how long do they hold on to the files before they are purged and unavailable. Obviously, the longer they hold on to files, the larger their systems have to be and the more money it will cost you. In addition to that, different services (and levels of service) will allow you to download only so much per month. Unlimited downloading comes at a premium. Often, the Newsreader will also cost money.

  Here is a little history on how the newsgoups work. As the name implies, a newsgroup was for news and acquiring news. It was mostly a text format only. However, if you "encode" a file- any file- it can be viewed as a text file. Obviously, it will just look like a bunch of jibberish but once you "decode" it, it turns back into the regular file. But most newsgroups only allow each message to be up to 50 megs. This is a pretty huge text file! But as for movie files? That's not so big. So what you have to do is- take this movie (or application), break it up into small parts, encode each small part and then upload each part to the newsgroup. Now others can download all of these parts, decode them and put them back together to reform the original file. Pretty slick, huh? The problem is that if you were to miss just one file (and a movie or large application could be hundreds of files), the file would fail to reform. So then someone came up with "par" files that will "fill in the missing parts" if a small number of parts are missing. This is great! But, it takes another program to assemble these parts. I use Unarchiver. Unarchiver will read "rar" files and "par" files making it a great choice for this method of file sharing. And just to share all of my secrets with you, I use Unison as a newsreader and Giganews as the Newsgroup service. Back in the day, you had to do a lot of research to find all parts of a file. But then someone came up with the "NZB". An NZB is a file that automatically locates all parts of a given file. This makes using newsgroups much more of a convenience. However, this means that your newsreader needs to know how to read NZBs (Unison does), AND, more importantly, now you must sign up for a service that offers these NZBs. This will also cost money most of the time. I use "NZBsRUS.com".

  Once you have all parts in place, not only are the downloads incredibly fast, but the quality is top notch. Often, you can find things in newsgroups that aren't available any place else. It is by far my prefered method of file sharing but again, it does cost me. And to think that this money is going towards all of these alternate methods instead of the proper people weighs a bit on my conscience. But, I get over it and sleep just fine.

  Let's imagine that you have a Mac and want to share a file with someone. If the other person has a Mac, there probably won't be any problem at all. You must know what kind of file that you are sharing. For instance, if you are sending someone an image, there should be absolutely no problems. But know that you are expecting them to have an "image viewer" installed on their machine. This is a safe assumption to make if your are sending an image to someone. But if you are sending someone a Word document, should you make that same assumption? Should you assume that everyone has Microsoft Word? Or worse yet, imagine that you are working on a Photoshop document. Photoshop is a $600 program and you cannot assume that everyone has it, much less the same version as you! In these cases, you'd want to save it AS a more generic file type. Save it as Text Only or RTF (Rich Text Format) so that some of the formatting will be retained. For images, save it as a JPG or a TIFF. Both of these formats are rather generic and any computer in the world today ought to be able to open these kinds of files. Keep in mind that the same editing capabilities will not be retained as with the proprietary format. For instance, all layers in a Photoshop file will be flattened if you send it out as a TIFF or JPG. Usually, two copies of the same file are created to accomodate sharing and editing.

  If the person you are sending a file to has a PC, then this presents one more hurdle. For the most part, sending them the file through the network, or internet or email is relatively problem free. Assuming that they have the program on their end required to open it, there shouldn't be any problems. But because you are dealing with different file system types, here are some suggestions to minimize potential problems.

  Keep your filenames simple. Do not use odd characters or spaces. And do not use the "." because that can force the end computer into thinking that the file is of a differnet type. Using the "/" can also be problematic because the end computer may think that you are trying to change directories. The same holds true for the ":". So to play it safe, just use the simple "alpha-numeric" characters and all should be good.

  If a network is not available to share files across and you must use either an external hard drive or jump drive, this adds another hurdle to this quest. Please refer to my article on "Jump Drives" because there is a significant difference in the file systems of a Mac and of a Windows machine. Basically, Windows will not recognize a Mac formatted volume. Although, a Mac WILL recognize a Windows formatted volume so depending on which direction you're going, you might be able to get away with it. Usually, copying files over a network is the best solution to these problems.

  This is a common question but I find it a bit odd. The real question is "What do you want to do with your Mac?" There are thousands of programs available to you but if you aren't going to make a movie for Hollywood, then you probably don't need Final Cut Pro. If you're not going to be multi-tracking the next one hit wonder for Sony Records, then you probably don't need Logic Studio 8. But, if you'd like to dabble with making movies or create your own soundtrack, then iLife would be perfect for you. Plus, it's only $79 so it is a no-brainer.

  iLife comes with iMovie, iDVD, iTunes, iPhoto, iWeb and GarageBand. iTunes is a free download and will come with every Mac. Obviously, this is for organizing your music, syncing your iPhone or iPod and purchasing music, movies, TV shows and iPod Touch or iPhone apps. This suite of programs is for your creative side and is most common on most Macs. If you think you're going to be doing more "serious" work, Apple has another suite of applications for you called iWork.

  iWork comes with 3 programs; Pages, Numbers and Keynote. This is very similar to Microsoft's "Office" suite. Pages is Word. Numbers is Excel. Keynote is Powerpoint. Also priced at $79, this is a great deal. However, some people just can't be without their Microsoft office so I have often recommended Office over iWork simply for the fact that it is already "known" and a learning curve won't be necessary. Not that iWork is difficult to use- typical of all Apple products, it is intuitive and elegant. And what's really nice is that iWork can open Office documents AND can save as Office documents so that you can share your work with your Window's unfortunates.

  There is one program that I find most people appreciate that isn't part of any suite as mentioned above. To edit images, manipulate photos and to get creative with pictures, Adobe Photoshop Elements is a perfect suggestion. It isn't the full-blown Photoshop but it offers a lot of nice tools and features that iPhoto does not offer. And for only $100, again, how can you go wrong?

  If on the other hand, you are looking to do professional work, not only should you have a MacBook Pro or a Mac Pro, but the software required is going to cost significantly more. There is the Adobe Creative Suite, Apple's Logic Studio and Apple's Final Cut Pro. These professional grade applications are pretty much industry standards. The full-blown version of Adobe's Creative Suite (CS4) costs about $2,800. Final Cut Pro costs about $1000 and Logic is only $500. I say "only" because for its capabilities, it is an incredible bargain! But again, this is not for the average user. These are designed for the professional in mind and required years of training and experience to master.

  iPhoto ’08 is a great update to the very popular iPhoto application that comes bundled with iLife. There is a new feature in iPhoto ’08 that is sort of a twist on an older feature that is still available in iLife ’06. When you import your photos from your digital camera, iPhoto will now categorize them automatically by the time stamp that your camera attaches to each photo. This is often very handy because it helps organize your imported photos immediately and automatically. iPhoto calls these grouped photos “Events.” Though this works perfectly most of the time, it is sometimes the case that you’ll want to merge 2 events together or split a single event into 2 events. The former is more obvious because there is actually a “merge” button on the bottom of the window. Plus, merging events is very intuitive- while in the Events view, simple drag one event onto another event and iPhoto will ask if you want to merge the two. But what if you want to do the opposite?

  In that case, simply double click on the event that you want to split. This will present you with a thumbnail view of all the photos in that event. Select the photo (by clicking on it once) that you want to split the event at. Then, from the menu up top called “Events,” select the option “Split Event.” iPhoto will then split the event into 2 different events and the split will occur at the photo you have selected. The photo that was selected will become the first photo of the new event. 

  You can also move photos from one event to another. In the column on the left, select “Photos” from the top and you’ll notice that all of your thumbnails are grouped together by event. Simply drag one photo (or multiple photos by holding the shift or command keys down)* and drag them to the appropriate event. Voila! The photos are now moved into that event.

*see the entry on multiple selections to clarify how you select multiple items. You have 2 different options.

  Disk Utility is located in the Utilities folder which is inside the Applications folder on the root of your hard drive (or top level). One of the most commonly used functions of this program is to format a drive. You can also burn CDs from this program, create images, erase CD-RWs, restore from images and perform two very important maintenance tasks.

  Notice in the photo that the drive that Disk Utility recognizes is a 232.9 GB drive. Really, the drive is 250 GB but about 5% of every drive is eaten up by the volume directory (or something like that). It is not usuable to you or the computer but is necessary for the hard drive. So it is common to see less that what you paid for here. If you click on the top most icon, you are selecting the entire physical hard drive as a whole. Reformat it and you lose all of your partitions (data included, obviously). Select one of the volumes below the physical drive, and you can modify just that volume (repair, erase, RAID,or restore). All partitions are volumes but not all volumes are partitions. (see disk images below).

  Below is a picture of the "Tabs" that are present when you select a volume. If you were to select the physical hard drive, another tab would be available called "Partition". This is what you'd select to break your physical hard disk into multiple volumes.

Format a drive

  To format a drive (or volume), simply select it in the column and hit the "Erase" button from the tabs up top. This will erase all data from the drive! You will not be able to erase or format your startup disk. That would be like giving yourself a lobotamy. Luckily, the OS prevents that possibility. Once you hit the "Erase" tab, the following should be visible in that window:

and from the Volume Format drop down menu:

  There should really be no reason to "Install Mac OS 9 Drivers" unless you have the Classic environment installed. By this time, hopefully everyone has retired their OS 9 applications and moved over to OS X. Leaving this checked will not affect anything even if you're in OS X. The most common format to use is the Mac OS Extended (Journaled) option. "Journaled" means that it keeps a record of trasactions so that in case of a crash, the OS is often able to restore your last transaction and hopefully, not lose any data. Do NOT rely on this. However, it is good to use this format for all Macintosh applications.

**For USB Flash drives, I usually have two drives; one that I share with friends and collegues and one for my own personal use. The one that I use for file sharing, I format to FAT32 so that my PC friends can read the drive. Most PCs cannot read an HFS+ (Mac OS Extended) formatted drive without 3rd party utilities. So this makes it much more compatible.

Maintenance

  Under the tab "First Aid" is where you can perform some simple maintenance tasks on your hard drive. It is recommended that you perform these tasks about once per month. Often, the system will work fine with minor errors. But those errors will only grow over time and lead to system instablilty. Eventually, your computer could fail to boot and all of your data is at risk. To avoid this, it is imperitive to be pro-active and perform these tasks on a regular basis. If you catch it early, repairing the errors is quick and easy. Letting it fester could lead to catastrophe. Please refer to my Mac Maintenance article for more info.

Optical Media

  This is also the application to use when you want to erase a re-writable CD or DVD. Simply put the disk in the drive, wait for it to show up in the list on the left and then click "Erase data on disc" in the window. There are actually on-screen instructions for this.

Disk Images and Restore

  A "disk image" is a type of file that when opened, becomes a mountable volume with its own file system. Often, this is how software developers bundle their software to be installed. The file looks like this:

 and then if you double click it, a new icon appears on the desktop that looks like this: 

  The "DiskImage.dmg" is a file that can be deleted. If you open it (by double clicking it) and mount the filesystem as seen in the second picture, then you can view it's contents. But this is usually a read-only volume (but not necessarily). More importantly, you do not delete the volume from the desktop but EJECT the volume as if it were a CD. If an application is delivered to you by means of a disc image, you should move the application to the Applications folder and run it from there. You can then eject the volume and even delete the disk image if you want.

  This is how you might want to copy a CD. You can create a disk image of a CD by going to the File Menu and selecting "New Disk Image from ...". Once the disk image is created, you can then "Burn" that disk image to a CD. You can also "restore" a disk image to a volume. This is how you can create a volume that is the Mac OS X installation DVD. You'll notice that the OS installs much faster from a Firewire drive than a DVD.

  There are more features and tasks that Disk Utility can perform but these features are less used and require a higher level of expertise so I will not go into it right now.

  Finding your IP Address in Mac OS X is simple. Just like on the previous page where we discussed application preferences, the entire system in general has preferences too. This can be found under the Apple Menu. Go to the Apple Menu > System Preferences > Network.

  There you will see a list of your network interfaces and their associated configurations. Displayed on the right is the Network control panel of a Leopard system (10.5). Tiger (10.4) will look a little different but the basics are exactly the same. Not only can you view your IP information here, but you can also modify all configurations from here. Within this window, on top, notice the drop down menu called “Location”. By default, it is set to automatic and an automatic configuration will work in most cases. This will set the system to use whichever interface detects a connection, will set it to acquire an address via DHCP and will use the fastest connection possible. Therefore, often, Built-In Ethernet is used over AirPort if both are available.

   Often, DNS Servers are not displayed if DHCP is used. To acquire your DNS addresses, you may have to go into the administration pages of your router. This is important to know how to do because your PUBLIC IP Address is different than your PRIVATE IP Address. The IP Address displayed in System Preferences will always show your PRIVATE IP Address if your computer is hooked up to a router. Otherwise, it will simply pass the Public IP Address to this Network Pane.

  Knowing how to get into your router to make necessary network adjustments is key for setting up any network. However, the means to do this varies depending on the manufacturer of the router. 

  On the Windows side of things, you might be familiar with the command “ipconfig /all” which displays all of your network information. This will give you your DNS addresses. If you go into “Terminal” on the Mac, you are now at a command prompt. By typing in “cat /etc/resolv.conf” and enter, terminal will respond with your DNS settings. The application Terminal is located in your Applications > Utilities folder.

What is your PUBLIC IP Address?

  Your public IP address is significantly different than your private IP Address. A private address is give to your computer by YOUR router. However, since your router (and network) is connected to a larger network (ie, the internet), your router receives its IP address from your ISP (Internet Service Provider). That is a public address. To find out what your public IP address is, simply go to the following link: www.whatismyip.com

  This is probably the easiest way to determine what your public IP address is. Basically, just like you can enter the IP address of a computer that is on your network and gain access to the machine (for file sharing, FTP, screen sharing, etc.), entering the public IP address will get you to someone's router (or entire network). This is why it is very important to configure your router appropriately so that not just anyone can gain access to your network or personal computers.