Tech Directions - March 2008 - (Page 13)

mastering computers 2 Reid Goldsborough reidgold@netaxs.com Deciphering E-mail Headers Have you ever been curious about the lines of what looks like gibberish in the headers of e-mail messages? An e-mail message’s header includes not only the From, To, Subject, and Date lines, but also a slew of other lines whose purpose and meaning are often far less clear. E-mail programs typically hide most of these lines from you, but you can view the full header with a few mouse clicks. In Microsoft Outlook, select “View” then “Options.” In Gmail, click “More Options,” then “Show Original” below the subject line. In Eudora, click “Show All Headers.” Other programs offer similar means of displaying these extra lines. Deciphering this information can indicate if the sender is faking who he is, give you information to stop the person if he’s stalking or harassing you, and tip you off on why your spam filter flagged the e-mail as spam. Perhaps the most interesting information in these lines is the IP, or Internet Protocol, address located in the Received line. An IP address is a computer address that identifies a device in a computer network, which typically is a computer but can also be a printer, router, or other device. An IP address, like a phone number or street address, is a unique identifier. IP addresses, however, can be hidden or shared in a way similar to that in which different phone extensions share the same company phone number. So it’s not a foolproof way of identifying who’s be- hind an e-mail address. Still, it’s often revealing. Look for the first string of numbers separated by periods in the Received line. One way to uncover the descriptive domain name associated with that IP address is to use the nslookup program on a Windows PC or a Mac. With Windows XP, click on the Start menu and select Run. Type the word “command” (without the quo- Perhaps the most interesting information in these lines is the IP, or Internet Protocol, address located in the Received line. tation marks) and press Enter. Type “nslookup” followed by a space and the IP address, and press Enter. The domain name will be returned in the Name line. Type “exit” and press Enter to close the command-prompt window. With Mac OS X, use the program www.techdirections.com MASTERING COMPUTERS 13 http://www.ljcreate.com http://www.studica.com/netop http://www.studica.com/netop http://www.ljcreate.com http://www.techdirections.com

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Tech Directions - March 2008 Technically Speaking Contents Direct from Washington The News Report Technology’s Past Technology Today Mastering Computers HDTV—Understanding the New, Dealing with the Old Technical Studies Lead to Dream Career Fill and Fund Your CAD Classroom with These Exciting Strategies STEM Progress in Katrina’s Wake School Web Site of the Month Spring Spotlight More than Fun

Tech Directions - March 2008

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