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1 C Switches operate at layer 2, the data link layer of the OSI model 2 D The standard connector for UTP in an Ethernet network is the RJ-45 connector An RJ-45 is larger than a standard phone connector 3 C A coaxial connector carries one wire, one physical circuit 4 D A DMZ based topology is designed to manage the different levels of trust between the Internet (untrusted) and the internal network (trusted) 5 A NAP (Network Access Protection) is one form of network access control 6 C The twist in twisted-pair wires reduces crosstalk between wires 7 B The shielding on STP is for grounding and reducing interference 8 D Microsoft Network Access Protection (NAP) enables the checking of a system s health and other policies prior to allowing connection 9 A Sniffing is the greatest threat, for passwords and accounts can be captured and used later 10 D The Simple Network Management Protocol is used to control network devices from a central control location 11 D Firewalls can do all of these things

12 A SMTP, the Simple Mail Transfer Protocol, is used to move e-mail across a network 13 C Microwave energy is a line-of-sight transmission medium; hence, towers must not be spaced too far apart or the horizon will block transmissions 14 D USB-based flash memory is low cost, fast, and high capacity currently 32GB 15 D Almost any digital memory containing device can find its way onto a network

In this chapter, you will Learn about the methods and protocols for remote access to networks Discover authentication, authorization, and accounting (AAA) protocols Be introduced to authentication methods and the security implications in their use Cover virtual private networks (VPNs) and their security aspects Explore Internet Protocol Security (IPsec) and its use in securing communications

Remote access enables users outside a network to have network access and privileges as if they were inside the network Being outside a network means that the user is working on a machine that is not physically connected to the network and must therefore establish a connection through a remote means, such as dialing in, connecting via the Internet, or connecting through a wireless connection A user accessing resources from the Internet through an Internet service provider (ISP) is also connecting remotely to the resources via the Internet Authentication is the process of establishing a user s identity to enable the granting of permissions To establish network connections, a variety of methods are used, which depend on network type, the hardware and software employed, and any security requirements Microsoft Windows has a specific server component called the Remote Access Service (RAS) that is designed to facilitate the management of remote access connections through dial-up modems Cisco has implemented a variety of remote access methods through its networking hardware and software UNIX systems also have builtin methods to enable remote access

The process of connecting by remote access involves two elements: a temporary network connection and a series of protocols to negotiate privileges and commands The temporary network connection can occur via a dial-up service, the Internet, wireless access, or any other method of connecting to a network Once the connection is made,

the primary issue is authenticating the identity of the user and establishing proper privileges for that user This is accomplished using a combination of protocols and the operating system on the host machine The three steps in the establishment of proper privileges are authentication, authorization, and accounting (AAA) Authentication is the matching of user-supplied credentials to previously stored credentials on a host machine, and it usually involves an account username and password Once the user is authenticated, the authorization step takes place Authorization is the granting of specific permissions based on the privileges held by the account Does the user have permission to use the network at this time, or is her use restricted Does the user have access to specific applications, such as mail and FTP, or are some of these restricted These checks are carried out as part of authorization, and in many cases this is a function of the operating system in conjunction with its established security policies A last function, accounting, is the collection of billing and other detail records Network access is often a billable function, and a log of how much time, bandwidth, file transfer space, or other resources were used needs to be maintained Other accounting functions include keeping detailed security logs to maintain an audit trail of tasks being performed All of these standard functions are part of normal and necessary overhead in maintaining a computer system, and the protocols used in remote access provide the necessary input for these functions By using encryption, remote access protocols can securely authenticate and authorize a user according to previously established privilege levels The authorization phase can keep unauthorized users out, but after that, encryption of the communications channel becomes very important in preventing nonauthorized users from breaking in on an authorized session and hijacking an authorized user s credentials As more and more networks rely on the Internet for connecting remote users, the need for and importance of remote access protocols and secure communication channels will continue to grow When a user dials in to the Internet through an ISP, this is similarly a case of remote access the user is establishing a connection to her ISP s network, and the same security issues apply The issue of authentication, the matching of user-supplied credentials to previously stored credentials on a host machine, is usually done via a user account name and password Once the user is authenticated, the authorization step takes place Access controls define what actions a user can perform or what objects a user is allowed to access Access controls are built upon the foundation of elements designed to facilitate the matching of a user to a process These elements are identification, authentication, and authorization