Network Administration: User Access and Permissions

Permissions enable you to fine-tune your network security by controlling access to specific network resources, such as files or printers, for individual users or groups. For example, you can set up permissions to allow users in the accounting department to access files in the server’s \ACCTG directory. Permissions can also enable some users to read certain files but not modify or delete them.

Each network operating system manages permissions in a different way. Whatever the details, the effect is that you can give permission to each user to access certain files, folders, or drives in certain ways.

Any permissions that you specify for a folder apply automatically to any of that folder’s subfolders, unless you explicitly specify a different set of permissions for the subfolder.

Windows refers to file system rights as permissions. Windows servers have six basic permissions. You can assign any combination of Windows permissions to a user or group for a given file or folder.

Windows Basic Permissions

Permission	Abbreviation	What the User Can Do
Read	R	The user can open and read the file.
Write	W	The user can open and write to the file.
Execute	X	The user can run the file.
Delete	D	The user can delete the file.
Change	P	The user can change the permissions for the file.
Take Ownership	O	The user can take ownership of the file.

In Windows, the concept of file or folder ownership is important. Every file or folder on a Windows server system has an owner. The owner is usually the user who creates the file or folder. However, ownership can be transferred from one user to another.

So why the Take Ownership permission? This permission prevents someone from creating a bogus file and giving ownership of it to you without your permission. Windows doesn’t allow you to give ownership of a file to another user. Instead, you can give another user the right to take ownership of the file. That user must then explicitly take ownership of the file.

You can use Windows permissions only for files or folders that are created on drives formatted as NTFS volumes. If you insist on using FAT or FAT32 for your Windows shared drives, you can’t protect individual files or folders on the drives. This is one of the main reasons for using NTFS for your Windows servers.

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Thwarting Spammers

Spam has been around since early in the life of the Internet, long before most people had even heard of it. In fact, the sending of "junk" electronic mail was such an issue that one of the Internet's earliest pioneers, Jon Postel, posted an advisory to his fellow developers (way back in 1975!) ranting and raving and expressing all kinds of frustration over this misuse of the network.

If you're equally angered by uninvited electronic correspondence, consider these ways to rid your cyber days of the e-mailed imposition:

• Know where your e-mail address can be found (white pages and Web pages, for example): Do you know who has your e-mail address? Do you participate in chat rooms? Message boards? Newsgroups? Do you have your e-mail address posted on your Web page?

Try putting your e-mail address into a search engine and seeing what pops up. The answer to the age-old question of "How did those #*%#$ get my e-mail address" may be that you gave it to them!

• Guard your primary e-mail address: When somebody asks for your e-mail address, think twice before giving it to him or her. Alternatively, shield yourself behind an e-mail alias.

• Use stand-alone e-mail software: Most Internet browsers come bundled with an e-mail program. The problem is that by bundling the two, you may be making it easy for hackers, spammers, and unscrupulous Webmasters to get your e-mail address from your browser. For that reason, think about using a stand-alone e-mail product, like Eudora, Outlook Express, installed with the Internet Explorer package), or Pegasus.

• Play hide-and-seek with your browser: Even if you're using a stand-alone e-mail program, you may have at some time recorded your e-mail address somewhere within your browser, or your browser may have even grabbed it and given it away for you in an attempt to be helpful. Because the whole purpose of a browser is to share information between computers, it may be giving away that information about you to others whenever they know the right way to ask for it. If you think that your browser may be blowing the whistle on you, here's how to shut down the little snitch:

• In Netscape: Choose Edit --> Preferences from the menu bar atop the browser window. In the list along the left side of the Preferences dialog box, click on the plus sign (+) next to Mail & Newsgroups. Then select Identity, which appears just below the plus sign. On the right side of the dialog box appears any of your personal information that the browser has stored. Erase all the personal information you see there and click OK to accept the changes.

• In Internet Explorer: Choose Tools --> Internet Options from the menu bar atop the browser window. In the Internet Options dialog box, select the Content tab and click on the My Profile button. Erase all personal information that appears on this form. Click OK to accept the changes.

• In Opera: Choose E-mail --> Edit Active Account from the menu bar atop the browser window. Erase all personal information that appears on the right side of the dialog box.

• Choose an ISP that actively blocks spam: Several of the large national ISPs — like AOL, Earthlink, and AT&T — have some spam-blocking features, so if yours has it, make sure that you use it. Although you'll have more difficulty finding a local ISP that blocks spam, many are run by system administrators who are veterans of the spam wars and know how to offer spam protection that makes nuclear missile silos look poorly defended, so it's always worth asking around.

• Find out how to filter your own e-mail: Some e-mail software programs have filtering features that, if you take the time to read the instructions, can be useful in helping you manage your mailbox in many ways, including helping you filter spam directly into the trash. Be ready to experiment with those settings, and don't auto delete anything until you're absolutely certain that your filters are working right. If your filter eats that e-mail from Aunt Ethel, you may get a cold reception (and dinner) when you head for her house next Thanksgiving.

• Never — never — click on Reply: Most return addresses in spam are faked to deflect complaints. However, some spammers use real addresses because they really do want to hear from you — but not for the reason you may think. Why would they want to hear your angry diatribe? When you click on Reply, you have just confirmed that your e-mail address is a "live one," which is like waving a big red flag and screaming, "This e-mail address is real! I really read this stuff! If you're smart, you'll send me more spam!"

• Find out how and where to complain to get spammers shut down: The best defense is a good offense. When spammers are offending you, offend them right back by finding out how to get them booted off their ISPs.

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Source:http://www.dummies.com/how-to/content/thwarting-spammers.html