Information Technology Reference
In-Depth Information
Text,
images,
scripts,
multimedia
e-mail
display
window
e-mail with
attachments
in MIME format
e-mail handler program
Handler
for word
processing
Handler
for
images
Handler
for
HTML
Handler
for
sound
Pop-up
window
Pop-up
window
Pop-up
window
Figure 13.6
Processing multimedia in email.
form designed for a word processor. Although such formatting
sometimes has benefits, it also can raise the same issues that we've
already discussed for browsers and scripting languages. Email at
tachments can contain scripts for scripting languages (such as
JavaScript), references to Web pages, embedded images, and the
like. Viewing any emailed material, therefore, can cause scripts to
run as programs, which, as we know, may or may not be a desired
effect. Although Figures 13.5 and 13.6 largely clarify how email is
processed, we will discuss some implications of this processing
shortly.
As you would expect for any communication via the Internet,
your email handler can report only the information it receives
within TCP/IP packets. Thus, your email handler naturally deter
mines the sender of an email based on the information it finds in the
email. There is no requirement that this information indicate the ac
tual sender of a message and no effective mechanism for checking.
This lack of a tie between actual sender and reported sender
may seem peculiar, but it can be quite helpful when applied to cer
tain situations. For example, for several years I have developed and
administered software for an international conference. Conference
