In addition to viruses and worms, there are some other annoying programs and files out there that
you need to protect your home network from. This chapter focuses on spam, cookies, spyware, and
scamswhat they are, how they work, and how to get rid of or at least control them. For the most
part, these types of files are not as dangerous as the others we discussed in Chapter 15, "Viruses and
Other Malicious Software"none of them will remove or destroy data for examplebut they are still
common, extremely annoying, and in some cases, they can do things without you knowing about it.
Spam is the common name for unsolicited commercial e-mail and it is a problem that is rampant on
the Internet today. Because of spam, a whole sub-industry of spam blockers has cropped up and is a
major concern of Internet service providers (ISPs). Major service providers claim that they block on
the order of 2 billion (yes, billion) unsolicited e-mails every day and have put the effort to stop spam
at the top of their priority lists. One of the reasons that spam is so widespread is that it is extremely
easy to send out millions and millions of e-mails with little cost.
How Spam Works
Spammers do their dirty work by purchasing or creating giant e-mail lists and automated mailing
tools calledspambots. The lists are usually compiled from web pages where people provide their email
address as part of a registration process. Usually, there is a box that is checked "yes" by default
saying something along the lines of "Yes, please share my e-mail with your sponsors for related
offers." If you agree, by leaving the box checked, you have just given the site permission to sell and
resell your e-mail address to spammers. Although most spam gets caught by filters or deleted by the
recipient, some of it is answered and that is why the spammers keep at it. It is really a matter of odds.
Even if the response rate is 0.5%, it cost next to nothing to send spam to upward of 10 million e-mail
addresses. At that rate, the spammer just pulled in 50,000 new customers.
How to Block Spam
There is a good chance that your ISP has some sort of spam-blocking feature available and, if spam
is a problem for you, we suggest starting there. Your ISP probably uses some basic filters such as
looking for keywords or multiple (100,000+) instances of an e-mail from the same source IP address.
Unfortunately, spammers (those who create and send spam) are pretty good at staying ahead of the ISPs
by using random or misspelled words or by constantly changing IP addresses as they send e-mails.
(There is also talk of anti-spam legislation, but spammers can easily set up shop in countries with looser
laws.) If the ISP filters are not blocking enough spam, you can purchase or download software that will
provide a second layer of protection on your system. Typically, these programs use advanced algorithms
to recognize and block spam but they are not perfect because sometimes spam gets through the filter,
and sometimes legitimate e-mail gets blocked (essentially a false positive). You can modify the options in
this program so that the blocking rules are customized. Be sure to check the folder that the spam blocker
drops trash e-mail into every once in a while to make sure you dont miss "real" e-mail.
We recommend that in addition to using the ISP and commercial blockers that you set up adirty e-mail
address. What we mean by dirty e-mail address is an e-mail address that is only used for the purpose
of registering on web pages. Given that most ISPs will allow several e-mail aliases with a standard
account, you can reserve one for this purpose and still have plenty for the legitimate users in the home.
After you do this, only give your "real" e-mail out to people you know and use the dirty one for everything
else. If you find that you do want some of the e-mail that comes into the dirty account, you can
notify the sender to use your real e-mail address. Keep in mind that most legitimate commercial sites
will not resell or share your e-mail address without your permission, but its up to you to make sure that
you read the fine print and uncheck any boxes that were pre-populated. This is always a red flag.
Turn on Spam Blocking at Your Service Provider
How to enable spam blocking with your service provider will vary highly and depend entirely on
how the ISP has chosen to set up its services.
Enabling the protection is very easy. Just follow these steps (in this example, EarthLink is the ISP):
Step 1 Log in to the EarthLink My Account page using your account user ID and password.
Step 2 Click Spam Blocker. Choose the blocking setting that is appropriate (see Figure 16-3).
There are three possible setting levels that we will take a moment to explain as they will also apply
to spam blocking on home computers (which we will set up next). The three settings and how they
¡ OffAll e-mail is forwarded; no spam checking is performed.
¡ MediumE-mail is checked against known spammer lists, and matches are discarded.
¡ HighIn addition to checks against known spammer lists, you create a list of e-mail senders that
are in your address book. Matches against the known spammer list are discarded. Matches from your
address book are forwarded to your inbox. If the sender is unknown (in neither list), the e-mail is
held as "suspected" spam. You then have to go in periodically and sort out acceptable e-mail from
If you receive e-mail from only a few known e-mail addresses (friends and relatives), put them in the
address book and turn the spam blocker on High. If you receive considerable e-mail from new
sources, you probably need to go with the Medium setting.
If your kids have e-mail accounts, we would highly recommend the High setting (no pun intended).
Kids should never receive e-mail from sources that you dont go in and specifically authorize.
Set Up Spam Blocking on Your Home Computers
If possible, set up a first line of spam defense in the service provider network. This may be enough,
so we recommend trying the ISP route first, and then see if you need additional protection.
If you need to enable blocking on each of the computers in your home network, as mentioned earlier,
most security bundles contain a spam blocking component. This section shows the steps to enable
First, its helpful to understand a bit about how a spam blocker works. Spam-blocker vendors maintain
lists of known spammers, which can be automatically updated on your home computers by the
security bundle software. Figure 16-4 shows the components of a typical spam blocker.
The spam blocker works much like the description in the previous section on service provider spam
blockers. There is typically a setting (like Medium) that discards e-mail matching known spammer
lists, and a higher setting (like High) that additionally compares against a personal address book that
you provide and maintain.
It is assumed that you already installed the security product bundle you have selected. Table 16-1
shows the process for enabling spam blocking on both the Symantec and McAfee products.
With the spam blocker enabled, you should see considerably less spam e-mail. We suggest starting
off with a Medium setting, and moving up to a higher setting if you are not satisfied with the reduction