Configuring Remote Connectivity


The capability to remotely access networks has become an important part of the modern IT infrastructure. All organizations, from the smallest business to the largest corporation, are taking advantage of the potential that remote network access provides. Therefore, today's network administrators are as likely to be responsible for managing remote network access as they are for LAN access. Configuring and managing remote access requires knowledge of the protocols and procedures involved in establishing a remote connection.

The following sections explore some of the common considerations in configuring a remote connection, including a discussion of physical connections, protocols (which facilitate the connection), software (which establishes the connection), the dial-up connection method, and security issues.

Despite the network operating system used, they all have remote connection technologies in common. Authentication protocols, physical connections, and such are common to popular OSs.


Physical Connections

There are many ways to connect to a remote network. Some, such as the Plain Old Telephone Service (POTS), offer a direct connection between you and the remote host. Others, such as cable and Digital Subscriber Lines (DSL), allow you to connect, but the connection occurs over a public network (the Internet), which can bring additional considerations such as authentication and security problems. The methods that can be used to establish a remote connection are discussed in Chapter 6. A summary is provided here:

  • Public switched telephone network (PSTN) The PSTN offers by far the most popular method of remote connectivity. A modem and a POTS line allow for inexpensive and somewhat reliable, if not fast, remote access.

  • Integrated Services Digital Network (ISDN) ISDN is a dial-up technology that works much like the PSTN, but instead of using analog signals to carry the data, ISDN uses digital signals. This makes it faster than the PSTN.

  • Cable In an effort to take advantage of the increasing demand for high-speed Internet access, cable TV providers now offer broadband Internet access over the same connection that is used to carry cable TV signals.

  • DSL DSL services are the telecom companies' broadband offering. xDSL (that is, the family of DSL services) comes in many varieties, and as with cable, you need a special modem in order to use it.

  • Satellite Perhaps the least popular of the connection methods discussed here, satellite provides wireless Internet access; although in some scenarios, a PSTN connection is also required for upstream access. Of the technologies discussed in this section, satellite is the least suitable for remote access.

  • Wireless Internet Wireless Internet access is provided by a Wireless Internet Service Provider (WISP). The WISP provides public wireless Internet access known as hotspots. Hotspots provide Internet access for mobile network devices such as laptops, handheld computers, and cell phones in airports, coffee shops, conference rooms, and so on. A hotspot is created using one or many wireless access points near the hotspot location. A hotspot typically requires a WAP at each location connected to a high speed broadband connection such as DSL, cable Internet, or even T1 connections. The technology is based on the 802.11 standards; typically, 802.11b/g and client systems require only an internal or external wireless adapter.

More information on remote access technologies and Internet technologies can be found in Chapter 6.


Protocols

When you have decided on the physical aspect of the connection, the next consideration is the protocols that allow you to make a connection to the remote server.

To facilitate a connection between a remote system and a remote access server, common protocols must be used between the systems. Two types of protocols are required to establish a remote connection. You first need to have the protocols that communicate at the data-link layer, including the following:

  • Point-to-Point Protocol (PPP) PPP is actually a family of protocols that work together to provide connection services. PPP enables remote clients and servers to negotiate authentication between devices. PPP can employ a variety of encryption methods to secure transmissions.

  • Serial Line Internet Protocol (SLIP) SLIP is an older connection protocol than PPP, and it was originally designed to enable data to be transmitted via Transmission Control Protocol/Internet Protocol (TCP/IP) over serial connections in a UNIX environment. Unfortunately, SLIP does not support encryption or authentication and therefore has largely fallen out of favor. If you have users that employ SLIP to connect from remote systems, you should move them to PPP connections as soon as possible.

  • Point-to-Point Protocol over Ethernet (PPPoE) PPPoE is a method of using PPP connections over Ethernet. Using PPPoE and a broadband connection such as xDSL or cable Internet access, it is possible for individual users to have authenticated access to high-speed data networks, which provides an efficient way to create a separate connection to a remote server for each user. This strategy allows Internet access and billing on a per-user basis rather than a per-site basis. Users accessing PPPoE connections require the same information as required with standard dial-up phone accounts, including a username and password combination. As with a dial-up PPP service, an Internet service provider (ISP) will most likely automatically assign configuration information such as the IP address, subnet mask, default gateway, and DNS server information.

After a data link has established the connection between the devices, LAN protocols are used. This includes TCP/IP, AppleTalk, and IPX/SPX.

Each of these remote access protocols require authentication protocols to complete the connection. Common authentication protocols include MS-CHAP, MS-CHAP v2, CHAP, PAP, or EAP. Each of these protocols is discussed in Chapter 6.


Many remote access products are available; however, Windows RAS is the most likely of these products to appear on the Network+ exam. RAS is reviewed in Chapter 6.




    Network+ Exam Cram 2
    Network+ Exam Cram 2
    ISBN: 078974905X
    EAN: N/A
    Year: 2003
    Pages: 194

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