Page 152 - StudyBook.pdf

136 Chapter 3 • Communication Security: Remote Access and Messaging

3. There are two types of VPNs: site-to-site and remote access.
4. Know your ports (PPTP, L2TP, SSH).
5. Know your transport protocols (RADIUS and TACACS use UDP,
TACACS+ uses TCP, and so forth).
6. TACACS+ was the first revision to offer secure communications
between the TACACS+ client and the TACACS+ server.
7. SSH is a cryptographically secure replacement for standard
Telnet, rlogin, RSH, and RCP commands.
8. Know the steps SSH uses to establish secure connections.
9. IPSec uses IKE and IKEv2 to manage keys. A SA can be estab-
lished either manually or through the use of ISAKMP.
10. Understand what types of vulnerabilities apply to all items
(802.1x, VPN, RADIUS, and so forth) as well as remote access as a
whole.

E-mail Security

Before continuing, let’s look at how e-mail is sent and where it goes.The term e-
mail is short for electronic mail and is, quite simply, an electronic letter that is sent over
a network. Mail clients are programs used to create, send, receive, and view e-mails.
Most current mail clients allow messages to be formatted in plain text or Hypertext
Markup Language (HTML).This means that e-mails can be simple text or they can
include formatted text, images, sounds, backgrounds, and other elements.
When sending e-mail messages, many stops occur along the way to its destina-
tion.The first stop is an e-mail server, which, in Figure 3.10, belongs to a ficticous
company, sendingcompany.com. Corporate e-mail servers typically run e-mail applica-
tions such as Microsoft Exchange, Lotus Notes, or Sendmail. Mail clients, however,
can be configured to use public mail servers like those provided by an ISP.These
are typically used by home users who are simply looking for POP mail hosting.
The clients used at home or in smaller businesses are typically free.Among these
applications are Outlook Express, Mozilla Thunderbird, Eudora, and now Windows
Live Mail.
The e-mail address is in the form of mailbox@domain (for example,
johndoe@mydomain.com). Note that it ends by denoting the top-level domain (such
as .com,.net,.org,.ca, and so on). For example, if an e-mail address is mybuddy@receiv-
ingcompany.com, the e-mail server sees that the top-level domain is.com.

www.syngress.com