Chapter 15

Internet Services and Email

FIGURE 15.0.F01: Elements of email format.

FIGURE 15.0.F02: Email in a rich text format.

Courtesy of Dr. Richard Smith

FIGURE 15.0.F03: Email text with MIME formatting.

TABLE 15.0.T01: Port numbers for email protocols

FIGURE 15.0.F04: Tracking an email’s journey.

FIGURE 15.0.F05: Following the email in Figure 15.4.

FIGURE 15.0.F06: Is this really an email from the president of the United States?

Used with permission from Microsoft

FIGURE 15.0.F07: Headers from the “presidential” email.

FIGURE 15.0.F08: Excerpt from a signed email message.

FIGURE 15.0.F09: A window from a 2003 phishing attack.

Courtesy of Dr. Richard Smith

TABLE 15.0.T02: A simple policy for managing an Internet connection

FIGURE 15.0.F10: Traffic controls involve different packet headers.

FIGURE 15.0.F11: Packet filtering examines individual packet fields.

FIGURE 15.0.F12: Session filtering keeps state across packets.

FIGURE 15.0.F13: Application filtering applies to multiple packets.

TABLE 15.0.T03: Format of simple firewall rules

TABLE 15.0.T04: Firewall controls to enforce Amalgamated’s Internet policy

FIGURE 15.0.F14: Single-firewall topology with an external bastion host.

FIGURE 15.0.F15: Three-legged firewall with a DMZ.

FIGURE 15.0.F16: Dual-firewall topology with a DMZ.