Read here to find all about it. Larry ----- Original Message ----- From: "Karen Kenworthy" <[EMAIL PROTECTED]> To: "Larry Braud" <[EMAIL PROTECTED]> Sent: Thursday, May 23, 2002 7:05 AM Subject: Karen's Power Tools Newsletter May 23, 2002
> KAREN'S POWER TOOLS NEWSLETTER > > ~~~~~~~~~~ This Week's Power Tools Sponsor ~~~~~~~~~~ > > Karen's Power Tools are now available on CD! > To learn all about it, and securely order online, > visit: http://www.karenware.com/cd.asp > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > May 23, 2002 > > By Karen Kenworthy > > Read the Web version of Power Tools online! > http://www.karenware.com/newsletters/2002/2002-05-23.asp > > IN THIS ISSUE > * IP Addresses > * ICANN, PPP and DHCP > * MAC Addresses > * All of Karen's "Power Tools" > * Subscription Information > > > Let's see ... I have a telephone number, a fax number, and a cell phone > number. I have a street address, two credit card numbers, a bank account > number, and a mortgage loan number. Then there's my auto club membership > number, my "Riders In The Sky" International Fan Club membership number, > and the number on my library card. Add to that several email addresses, > login names at several web sites and online services, and a few account > numbers at "brick and mortar" stores I frequent. > > Whew! That's nowhere near a complete list. But you get the idea. We humans > love giving each other "IDs", names or numbers that identify us. > > Our computers enjoy this sport too. From drive letters, to port numbers, > to login names, computers love to assign IDs. Today, let's take a close > look at two forms of computer ID -- one an old friend, IP Addresses, and > the other new friend, the MAC Address ... > > > IP Addresses > ------------ > We've talked about IP Addresses before. The letters "IP" stand for > "Internet Protocol," and each computer connected to the Internet must have > at least one. Think of these unique numbers as your computer's > "membership" number, assigned when it joins the Internet. Without an IP > address, your computer can't play on the 'Net. > > Now you may be wondering, "What do IP addresses look like?" The answer > depends on who you ask. True to their numerical nature, our computers see > IP addresses as 32-bit binary numbers. For example, to them, the IP > address of one of Microsoft's web servers looks like this: > > 1100 1111 0010 1110 1110 0110 1101 1011 > > But we humans don't get along well with long strings of 1s and 0s. We > prefer numbers with a wider variety of digits, preferably digits ranging > from 0 to 9. These are what mathematicians call "decimal" numbers. > > So you might think that humans would convert binary IP addresses into a > large decimal number. If they did, the IP address shown above would look > like this: > > 3,475,957,467 > > But if that doesn't look familiar, you're not alone. In fact, thanks to > some clever network designers with time on their hands, human-friendly IP > addresses actually look like this: > > 207.46.230.219 > > The "recipe" for creating this "dotted quad" form of an IP address is > simple. First, divide the 32-bit IP into four equal parts, containing 8 > bits each. Next, convert each of these 8-bit binary number into its > decimal equivalent. These decimal numbers will fall between 0 and 255 (the > smallest, and largest, possible values of an 8-bit binary number, > respectively). Finally, add periods to taste. :) > > > ICANN, PPP and DHCP > ------------------- > I guess every parent has to answer this embarrassing question, sooner or > later. "Mommy, Daddy, where do IP addresses come from?" Of course, you can > give the simple, easy answer -- "Why, IP addresses come from ICANN (The > Internet Corporation for Assigned Names and Numbers)" then quickly change > the subject. > > But while this reply might satisfy a young child's curiosity, you and I > know the real answer is much more complicated ... > > Unlike the early days of the Internet, today ICANN doesn't directly supply > IP addresses to any computer or network. Instead, ICANN divided most of > the available IP addresses into three large groups, and has given one > group to each of three "Regional Internet Registries" (RIRs). > > That doesn't sound too complicated, does it? For example, Europeans might > get addresses from RIPE, or the "Reseaux IP Europeens." Asians could get > an IP address from APNIC (the "Asia Pacific Network Information Centre"), > while folks living North and South America would shop for their addresses > at ARIN (the "American Registry for Internet Numbers"). > > But of course, things aren't that simple. Only the largest companies and > Internet Service Providers (ISPs) obtain IP addresses directly from a RIR. > The Registry's give away addresses a few million at a time. Those who need > "only" a few thousand IP addresses, let alone folks who need only one or > two, need not apply. > > Large companies divide the IP addresses they've received among > subsidiaries and their large networks. From there they eventually find > their way to individual computers. Large ISP's allocate IP addresses to > their customers, some of which are smaller ISPs. Eventually, these IP > addresses, too, make their way to small networks and single computers. > > > But how? How do computer's discover the IP address they've been given from > on high? > > Some computers are assigned "static" IP addresses, addresses that don't > change over time. Often these computers operate web sites, or provide > other public services. Keeping their IP address constant makes life easier > for the rest of the Internet world that must communicate with them. > Normally, a system administrator "tells" each of these computers their IP > address. > > But most computers on the Internet have temporary, or "dynamic" IP > addresses. Over time, these addresses can, and do, change. For example, if > you connect to the Internet via a modem and a phone call, an IP address is > assigned by your ISP for the duration of your connection. This assignment > of the IP address (plus the exchange of your ISP account name and > password) is handled by something Internet experts call Point-to-Point > Protocol, or PPP. > > Computers attached to a Local Area Network (LAN) learn of their IP > addresses in a different way. In most cases, they contact a special > computer on the network, known as a DHCP (Dynamic Host Configuration > Protocol) server. Computers with "always on" connections to the Internet, > such as cable modems or DSL lines, must contact a DHCP server too. > > When contacted, this server loans, or "leases," IP addresses to other > computers. The term of these leases lasts for a few hours, up to a few > days. Once a lease has expired, the computer must contact the DHCP server > again, to renew its lease or obtain a new IP address. > > > MAC Addresses > ------------- > The sharp-eyed among us may be wondering, "How can a computer communicate > with a DHCP server, to obtain an IP address?" After all, aren't IP > addresses used when sending information between computers? > > To find the answer, let's look at the special circuitry a computer uses > when communicating over a LAN, or other broadband pathway such as a DSL > line or cable modem. It's called a Network Interface Card (NIC), because > it connects a computer to a network (your LAN, or the network of your > ISP). > > At one time almost all NICs resided on a separate circuit card, called a > network adapter, hidden inside your computer. But today, a NIC may be > built into the circuits found on a computer's motherboard. In the case of > laptops, a NIC may even be inserted into a special opening called the > PCMCIA or PC Card slot. > > Wherever it's found, permanently stored within the NIC is a unique 48-bit > binary number called the MAC (Media Access Control) Address. And it's by > this MAC address that each NIC is known, within a local network. > > Our electronic friends only appear to use IP addresses when sending > messages across a LAN. Unseen, our computers translate each IP address > into a corresponding MAC address, and use the MAC address to route each > packet of data. And when talking to a DHCP server, they can even eliminate > that conversion, using the server's MAC address directly. > > > To make sure every MAC addresses is unique, the first 24 bits of the > address identify the NIC's manufacturer. Manufacturer's are assigned these > numbers, called an Organizationally Unique Identifier (OUI), by the > Institute of Electrical and Electronics Engineers (IEEE). > > The remaining 24 bits of each MAC address are a serial number, assigned to > a particular NIC when it is made. This allows each manufacturer to create > a maximum of 16,777,215 (the largest possible 24-bit number) NICs. When > that limit is reached, the manufacturer must reapply to the IEEE for > another OUI. > > This arrangement allows you to determine the manufacturer of a NIC, if you > know the NIC's MAC address. Simply enter the first 24 bits of the MAC > address (in hexadecimal notation) at this section of the IEEE's web site: > > http://standards.ieee.org/regauth/oui/ > > While there you can also apply for an OUI of your own. They're only > $1,650. :) > > > To discover the MAC address of all NICs found in your computer, check out > Karen's Computer Profiler at: > > http://www.karenware.com/powertools/ptprofiler.asp > > This program will also reveal the IP addresses assigned to your computer. > And unlike an OUI, the Computer Profiler is free. :) > > > You might also want to try Karen's URL Discombobulator, a program that can > disclose the IP addresses assigned to any remote computer with a domain > name, such as www.microsoft.com. Another Power Tool, Karen's WhoIs, can > even tell you which RIR, and which company or ISP, was allocated that IP > address. You'll find these two programs at: > > http://www.karenware.com/powertools/ptlookup.asp > http://www.karenware.com/powertools/ptwhois.asp > > And as always, if you prefer the convenience of a CD or want to support > Karen's Power Tools, visit my CD home page at: > > http://www.karenware.com/cd.asp > > There you can order your own copy of Karen's CD, complete with the latest > Computer Profiler, URL Discombobulator, and WhoIs. Your CD will also > include the most recent versions of every Power Tool, plus three bonus > Power Tools programs not available anywhere else. The CD even has all the > back issues of my newsletters, and a special license that lets you use all > the Power Tools at work! > > > As for me, I may spend some time listening to the "Always Drink Upstream > From The Herd" CD by "Riders In The Sky." Their version of Gene Autry's > hit "Take Me Back To My Boots And Saddle" can't be beat! If you're a > secret buckaroo or buckarette, you might want to find a copy, kick off > your boots, and have a listen too. > > And if you see me riding the range, or cruising the 'net, be sure to wave > and say "Hi!" After all, it's the Cowboy Way. :) > > > Karen > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Visit Karen's Power Tools Store and check out the newest > Power Tools T-shirts, mouse pads, hats, tote bags, mugs, > and more! A portion of the price of each item helps > keep Karen's Power Tools newsletter and programs free. > > http://www.karenware.com/store.asp > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > All of Karen's Power Tools > -------------------------- > Note: For the most up-to-date list, visit: > http://www.karenware.com/powertools.asp > > * Computer Profiler - http://www.karenware.com/powertools/ptprofiler.asp > * Countdown Timer II - http://www.karenware.com/powertools/ptcount2.asp > WhoIs - http://www.karenware.com/powertools/ptwhois.asp > URL Discombobulator - http://www.karenware.com/powertools/ptlookup.asp > Replicator - http://www.karenware.com/powertools/ptreplicator.asp > Directory Printer - http://www.karenware.com/powertools/ptdirprn.asp > Version Browser - http://www.karenware.com/powertools/ptbrowse.asp > 'Net Monitor - http://www.karenware.com/powertools/ptnetmon.asp > Power Toy - http://www.karenware.com/powertools/pttoy.asp > Drive Info - http://www.karenware.com/powertools/ptdinfo.asp > Disk Slack Checker - http://www.karenware.com/powertools/ptslack.asp > Window Watcher - http://www.karenware.com/powertools/ptwinwatch.asp > Autorun.inf Editor - http://www.karenware.com/powertools/ptautorun.asp > Cookie Viewer - http://www.karenware.com/powertools/ptcookie.asp > Registry Pruner - http://www.karenware.com/powertools/ptpruner.asp > Registry Ripper - http://www.karenware.com/powertools/ptregrip.asp > Font Explorer - http://www.karenware.com/powertools/ptfonts.asp > Snooper - http://www.karenware.com/powertools/ptsnoop.asp > Countdown Timer - http://www.karenware.com/powertools/ptcount.asp > Alarm Clock - http://www.karenware.com/powertools/ptalarm.asp > Print Logger - http://www.karenware.com/powertools/ptprnlog.asp > Mailer - http://www.karenware.com/powertools/ptmailer.asp > Clipboard Viewer - http://www.karenware.com/powertools/ptclpvue.asp > > * Indicates program was updated recently. > > NOTE: You should use Control Panel's Add/Remove Programs applet to > remove the old version, before installing a new version of a Power Tool. > > Note: Be sure to install the Visual Basic Runtime v6.0 before installing > your first Power Tool. It's required by all the Power Tools, and must be > installed first. You can download a copy of the Visual Basic Runtime v6.0 > installer, vbrun60-setup.exe, from any of the pages where you download the > Power Tools themselves, or from my special Runtimes page at: > http://www.karenware.com/runtimes.asp > > > -- K-A-R-E-N-'-S--P-O-W-E-R-T-O-O-L-S -------------------- > Copyright 2002 Karen Kenworthy > http://www.karenware.com/ > > > Subscription Information > ------------------------ > To subscribe to this newsletter, visit http://www.karenware.com/subscribe/ > or send a message from the email account where you'd like to receive the > newsletter to: [EMAIL PROTECTED] > > To change or cancel your subscription, click this custom link to Karen's > Power Tools Newsletter Subscription Center: > > https://secure.karenware.com/[EMAIL PROTECTED]&id=25679 > > You can also cancel your subscription by sending a message, from the email > account where you are subscribed, to: [EMAIL PROTECTED] > > This Newsletter was Sent to: [EMAIL PROTECTED] > Your Subscriber ID is: 25679 > > >
